My F30 is very new, but so far I have had no problems if I format the card in the camera each time I start a new shoot (or after downloading all pics on to PC). I've been doing this with my DSLR, and older P&S, no prob ever. I have seen probs when I deleted some pics thru a PC, put the same card back into a different cam and shoot - the cam tried to shoot but couldn't save the image.
Try using a CF-xD adapter. Works almost 100%. I know it's a workaround...but it works!