I'm having problems with my game too.
i bought it from steam and when i try to join one 9444 patched dayz server, i got the "Bad Version" warning.
When i try to install the 9444 beta patch it gives me the "Wrong CD Key" warning.
So, i've tried to validate cache and it said that one file failed to validate and will be reacquired on both ARMA2 and ARMA2 OA.
So, i'm pretty much stucked here since i dont have nothing else to do besides reinstalling the game which i'd like to avoid for now since my internet is slow,200kpbs. (and i'm not considering giving my CD Key to no one at all)