The installer gets pretty far every time, but then sometime after it patches the Engine file it claims I have changed my files in some way, which I havent. I even just reinstalled DC and it still did it.
I am not running any no-cd's or cracks or anything of that sort. I legally own the game and don't use any kind of cracks or anything else that would change my game files.
EDIT: Nevermind, got it to work on my own...rest assured, it was something stupid and not my fault :P