If your Guest list is always being reset, or 'erased', then I am guessing mysql is reseting itself. You need to look in your mysql error logs to see if this is happening. (I could have sworn you already posted about this and I suggested the exact same thing. edit: I did -
Sometimes my guest always Kick Out)
For more reading about the errors:
MySQL Server has gone away:
http://www.vbulletin.com/docs/html/t...mysql_goneaway
MySQL can't connect:
http://www.vbulletin.com/docs/html/cantconnect