Cannot mount iPod shuffle into ubuntu 11.10

I have a problem with my iPod shuffle. I can't mount it in Ubuntu 11.10. I plug it into the USB port, but it doesn't recognize it. I can't find the mount directories. I installed Rhythmbox, but it doesn't recognize it either. I checked /mnt, there are no files. I don't know what else to do. Any ideas? Thanks for your help
