BP Mass Messenger Help

Hi guys,
After reading your BP article posted on facebook here:

https://premium.wpmudev.org/blog/how-to-send-a-site-wide-notice-or-a-site-wide-private-message-in-buddypress/

I installed the plugin and just sent my first message to the entire site. Good news is it worked.
Bad news is that after sending it I get these error messages. LOTS OF THEM. I write the message and click send. The error messages appear but it appears the messages sent fine though so I don't know what these refer too. Any ideas?

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 549

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 550

Warning: Cannot modify header information - headers already sent by (output started at /home/sharespe/public_html/wp-admin/admin-header.php:19) in /home/sharespe/public_html/wp-content/plugins/buddypress/bp-messages.php on line 551