Conflict between eNewsletter and bbpress

I tried to activate both PHP mail and wp mail in eNewsletter on the settings page. The following error came through.

Warning: in_array() expects parameter 2 to be array, null given in /home/rvhobo7663/public_html/wp-content/plugins/bbpress/includes/common/functions.php on line 1446

Warning: Cannot modify header information - headers already sent by (output started at /home/rvhobo7663/public_html/wp-content/plugins/bbpress/includes/common/functions.php:1446) in /home/rvhobo7663/public_html/wp-includes/pluggable.php on line 1167