Simply put:  Spambots are trying to break into user's accounts by spamming the forum with log-in attempts.  The flood control kicks in and logs the user off the forum.

- Make sure you have a strong password so the robots can't get in.

- I upgraded the forum to the newest and most secure version, but it hasn't seemed to fix the problem.

- So at the moment, I'm not quite sure what to do as a fix.  I'm really sorry for the constant sign outs, and I'll fix it as soon as I know how.