Sorry if this has already been asked, I looked a little but didn't see anything.

Whenever I kick someone, they apparently recieve a "bad packet" error so that they don't even knoe they were kicked.
Furthermore - and this is all I can verify for certain - when a banned player tries to join my game, there's an error that the player "(name)" has no brick group, and BL crashes. So, instead of not being able to join my game, anyone I've banned can instantly crash the server just by trying to join it. As such, I can only repeatedly kick people, and heaven forbid I go AFK lest they return.
What can I do to fix this?