I had a problem like that, but the problem was my computer's card reader. I got a (universal) usb port card reader (targus) at radio shack ($19.99) and it reads all the cards I have. maybe that would work for you. Does you computer read from the card when you used the other camera?
Thanks for the info. by the way do you know if there is a way to recover from a zen creative vision m? Same problem the program won't read the player. I didn't even look at the date, just searched for the topic and this is the one that came up.