Warning: strstr(): Empty needle in /home3/filmfilm/public_html/

when i go to view a profile or anything that has to do with buddy press. this appears:
<b>Warning</b>: strstr(): Empty needle in <b>/home3/filmfilm/public_html/wp-content/plugins/buddypress/bp-core/bp-core-filters.php</b> on line <b>641</b>

this appears as the name of my tab. as the <title> when i go to view source. what does this mean and how do i get rid of it?