My brother installed, and tried to log in, after improperly typing in the CD-Key, and this error kept coming up, even though he was able to log into and WoW. I had him try to log in on my computer, as I'd been able to get in, and his log in info worked fine, but not on his. I had him uninstall the game, but more than that, hunt down all the saved settings under his windows username, and in program files, and delete everything having to do with this game. Reinstalled off the disc, and updated all files, and the game works fine now.