php warning

Hi Keith i’m seeing this show up in my logs do you know what this issue is and how to fix?

[01-Aug-2013 01:46:13 UTC] PHP Warning: session_start() [function.session-start]: Cannot send session cache limiter – headers already sent (output started at /myserverroot/mysite.com/web/content/wp-content/plugins/buddypress/bp-themes/bp-default/_inc/ajax.php:106) in /myserverroot/mysite.com/web/content/wp-content/plugins/stop-spammer-registrations-plugin/stop-spammer-registrations.php on line 72

thanks

http://ww.wp.xz.cn/plugins/stop-spammer-registrations-plugin/