Be sure that you are running the latest version of the camera firmware (currently 3.0.14). Even if you are, try reloading it. If that doesn't work, try reverting to an older version, then reloading the latest version. If none of this works, the camera will likely have to take a vacation in Rochester, NY.
Be sure to try different cards in the bottom slot (different brands, if possible) during this troubleshooting routine.
Good Luck and let us know how it turns out,
Tom DeRousie
http://www.modernimaging.com