@froggman from the manual:

The following issue can cause a File Error message:

• The picture file is corrupted
• The picture was taken with a different manufacturer's camerahe memory card inside your camera is not formatted
• The memory card in the camera is not compatible or defective and needs to be repalced.

I'd start with formatting the card and see if that works. If not replace it with a new one. you can get the user manual from here which tells you how to format the card etc.