"Headers-Error" sounds more like an incomplete or corrupted download (as in "corrupted archive"). You should download it again, maybe from a different source or using a download manager to make sure your download is correct...?!
Also: when there are different sites you can download it from, and you claim "the Game files are infected", you should probably add from which site you've downloaded from. Nobody is going to download the game five times to check if something is infected. Because the files I downloaded had no errors and weren't infected, and I've downloaded them through Mega IIRC.