I'm not at home so I can't test it out, but try playing around with the camera's clipping plane.

It's just a wild shot in the dark and the first thing that came to mind when I saw your screenshot.

Edit: Sorry, forgot to mention...If your camera has a really low clipping plane and a really high clipping plane, it can cause rendering artifacts to appear. If I remember right, it has something to do with the mathmatical equations trying to determine the dept if the clipping range is really far apart.