problem with r4 card

Can anyone help.
I have 2 r4 cards for the kids.
one works fine, the other hangs all the time.
I emptied the hang card and reloaded it and it does the same. Both cards have the same stuff on them and I can read the card when it is in the chip reader on the PC.Any sugestions as my kid is upset

It can be a problem with the SD card - try this as it really can work.Re format the SD card usinghttp://panasonic.jp/support/global/cs/sd/download/sd_formatter.htmlput everything back on and try again. This only works under windows, as windows does not format SD cards correctly.