I was on Killerbee's Nali Waepons 2 Monster Hunt server last night when something odd happened. I got booted out of the game. Tried reconnecting 3 times but I kept getting the same error message. Ultimately I had to exit ut99 entirely, go back in again, and then everything worked fine. Still, the error message doesn't make any sense to me.
I screenshot it:

What does that mean?
Any clue what might've caused it?