I have the SAME exact issue! I have a digitally distributed version of COD4, and I have updated PB like 10 times..
I keep getting kicked 5 mins or so into my game for Error #80310, GAMEHACK. I'm not hacking, and if I were I wouldn't be dumb enough to ask why i'm getting kicked! Please help, this is very aggravating, and the last thing I need is my COD4 account getting wrongly banned..