I don't think there is a real fix for this problem, other than sending it to Casio and I believe they will charge quite a high proportion of the camera's value.
If you have the newer firmware in your camera then the message appears for a couple of seconds then dissapears and you can use the camera as normal. (The image stabilizer won't work for still photos, but the video stabilizer which I think is just done in software appears to be ok).
If you have old firmware you will just get the error message and won't be able to use the camera at all in any mode. If yours is like this then download the new firmware from Casio's service website and follow their instructions to install it. (Make sure your battery is fully charged before Flashing the new firmware etc).
The message still displays for a couple of seconds each time you switch to camera mode which is anoying, but at least you can use the camera if you can put up with that).
SkySurfer, July 2009