My copy arrived today and when I input my product key I get an error message that says "this content is not available for download in your country". Now for a second I thought I had been really dumb and ordered a US copy or something but I have not.

Has this happened to anyone else? This is the first issue I've had like this.

First of many from what I heard of this games amount of bugs.

hmmm, where are you ordering from? and what country you are in? I bought DMC from UK steam key and that worked. And I have friends in Germany who have to travel to Austria to get uncensored games that have green blood or robots. I'd say call their tech support, and be persistent and explain your situation. Most tech support want to help you, so you might luck out and get some extra gifts out of it.