Fatal Error

Hello I am trying the plugin today, and to try post a comment with a name/email in the database forum spam, I get this error:

Fatal error: Call to undefined function is_bbpress() in /home/tudinero/public_html/wp-content/plugins/wp-stop-forum-spam/stop_forum_spam.php on line 102

http://ww.wp.xz.cn/extend/plugins/wp-stop-forum-spam/