Same error here.. usign wine 1.3.4 ive downloaded 8 Gb all over from blizzard account site, then it started downloading 4 gb of patches.. this second download failed at some point.... i dont know when... then i started the game, got the cataclysm screen also... loged myself in, and once the download started i got the same error as you guys got... ubuntu 10.10 here hope we can fix this soon! best regards