As far as I know, the Cromwell BIOS will not allow you to play backup copies of your games, so I would image that you are running some other BIOS, be it a version of the X2 or a EvoX BIOS.
If you happen to be running Evolution X (make sure it's the latest version - 3935) then you'll need to read the manual from the Team Xodus website to reflash your Chameleon with a new BIOS. The manual is located here :
Chameleon User's Manual v1.3. If not, then you can either install Evolution X as an alternative dashboard to help you in this matter, or you can look for a programmer and use the software from the Team Xodus website to reflash it that way.