*** HELP - OS X Is erasing my Compact Flash Cards ***

I am behind the times, and JUST NOW installed OS 10.1.? on my iMac 350..... Anyway, OS 9 treated my CP Flash okay. But OSX has render my cards UNREADABLE in my camera. I cannot even re-format them in the camera. Its like they dont even exist. However, they are still readable in a Windows environment (ugh). I have screwed up TWO cards already, dont want to risk my 3rd and final card.

Any ideas?

Thanx