I have downloaded the game 3 times now, and every time It will tell me that one of the files (a different file everytime) is corrupted and refuses to install. Anyone else having trouble with this?

I downloaded this game between last night and today, some files last night and the others today in the morning (bonus included), and I didn't have any problem. The setup checked the game and everything was OK. I didn't use any downloader, just my browser (Firefox 8.0.1).

Maybe is the program you're using to download the files, or, let's hope not, your hard drive. Try again with a different software (or computer).

I used gog downloader as well but no corruption occurred. Maybe your connection has been breaking and gog downloader couldn't resume it properly. You said it's different file everytime, so maybe try to save those files which aren't corrupted and manually redownload corrupted ones.