Ooops. I just got a white screen with the following; I had just created a test user group, and I think I had just clicked on Today's posts or private messages (sorry, I was so surprised I don't recall) and got:
Warning: require([path]/modules/onlineusers.php) [function.require]: failed to open stream: No such file or directory in [path]/includes/vba_cmps_include_top.php on line 296
Fatal error: require() [function.require]: Failed opening required '/home/puritanb/public_html/modules/onlineusers.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/puritanb/public_html/includes/vba_cmps_include_top.php on line 296