Unable to authenticate error after install...........what is the effin problem? The cd copy work around (official fix) didn't work. PLEASE help!

Are you talking about a CD Key error? When I tried to install the game, it told me me CD was invalid. I typed it many times, in upper and lower case, as well as using letters that look similar (i.e. G in place of C, or E in place of F) and I still couldn't install the game. Anyone have a similar problem? (and yes, I have a legal copy that was not a resale or copy).