Fatal Error in BuddyPress Group Frontend

I'm using WP 3.5.2 with BP 1.8.1 and got the following message in the admin frontend of a BuddyPress Group: "Fatal error: Call to a member function add_tip() on a non-object in /home/…/public_html/…/wp-content/plugins/wordpress-chat/lib/wpmudev_chat_admin_panels_help.php on line 608"