brought the game on steam used the 2 codes i got from white dwarf mag to add extra content and get money off game, as soon as i loaded the game up it pops up authentication error on the title screen and i cant play the game! it worked fine for my friend so i went over there and it works fine! i made an account played for and hour, went back home to play on my PC and still the same things still happens .. even after uninstalling the game and reinstalling it .. 3 Times! can anyone help me??