Fatal error: require_once() [function.require]: Failed opening required '/home/*/*forums/Sources/Subs-MembersOnlineToday.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/*/*forums/Sources/BoardIndex.php on line 81
make sure the file was actually and fully uploaded...
Sometimes FTP clients will choke on one or more files.
I got this resolved, I ran the update again.