It's unlikely that it has anything to do with firmware.
It's more likely that you have defective batteries or dirty contacts in the camera's battery compartment. If nothing else, clean them with a pencil eraser (or a Q-Tip with a touch of alcohol on it).
Most store bought Isopropyl alcohol is not recommended for this purpose though (as it has a high water content). But, I'd personally use it in a pinch, making sure the contacts were dry afterwards. Use at your own risk. BTW, Radio Shack sells a contact cleaner pen that's designed for this purpose.
Have you tried known good (i.e, fresh), fully charged, high capacity (i.e., > 2000mAh) NIMH batteries in it? Some models won't even power up for more than a few shots with Alkalines. I don't know if your Casio falls into this class of camera or not.
http://www.steves-digicams.com/nimh_batteries.html
If the battery contacts are clean (and you can't always tell by looking at them if oxidation on contacts is causing a problem), and the batteries are known good, fully charged, high capacity NiMH cells, then you may have a component failure of some type.
I'd make sure to use all switches, dials and buttons, just in case one of them has a bit of oxidation under it causing an issue. I'd also try a different memory card if you have one (just in case it's defective and shorting out the camera).