I've seen a lot of threads on this subject. I think one of the solutions was to actually push on the camera lens, as if it had come loose.
If I were you, I would type about 4 or 5 words of the exact message into the search engine here and read through a few of the bigger threads you find. If you don't find a solution, you could try updating the OS to the latest of .151. If that doesn't help either, I'd take it in to a store for a replacement.