Black Textures

I have a problem where the textures are black, at first its was small things but now i cant see anything because of this. Here is a screenshot of it.

http://cloud-4.steamusercontent.com/ugc/540768312200014415/CA4BF1E7F66C7AC177431A1D4E4193DAF9C2B3FB/1024x640.resizedimage

How can i fix this?