Me and my buddy have this problem also occasionally on our normal win 7 64bit pc's. sometimes takes an hour to get on because of initialization error, or an update problem. GG itself just blows balls. Sometimes just rebooting will fix it. Or waiting an extended period of time. Other times it just randomly will start working. I get the error also when i will be already logged on account and try to open another client also. Plain and simple. Gamegaurd sucks ass.