Well, it confirms what I know already, and I don't think you caused it. Sometime that evening, the user database locked it's self (a protection to prevent more damage usually), and when I unlocked it, 6 users were gone. The 6 people affected were on the board at the time.

I didn't see your name in the list when I compaired the database to the backup for some reason though. I'll count up your posts and update your post count here shortly.

edit: Although, you have pinpointed the time closer then I knew about, and that might help. The server keeps logs of all the SQL traffic, and now I can look at a smaller timeframe for errors.