The botgroup table will probably only be populated when you actually have a bot that's grouped. That's just where it grabs the data from to decide if it needs to spawn bots for you after you zone.
Something that someone mentioned a while back was that they couldn't delete bots and it was because of some character set mismatch in the database. At the time I looked at mine and it also seemed like it was mismatched in the same way but I wasn't having any problems. I'm no database genius, so I don't know if that's relevant or not, but it might explain some of the spurious issues people have. *shrug*
Anyway, glad it works now.
