If you have not already done so, reset the camera using the attached instructions and please let me know the result.
Remove the lens, memory card and battery.
Switch the ON/OFF switch to ON.
Allow the camera to sit idle for 30 minutes.
Switch the ON/OFF switch to OFF.
Insert the battery only.
Power the camera on. If the error is gone, mount the lens and insert the memory card.
If not, please let me know.
By the way, has the unit been subjected to any hard impacts?