iPod Classic Not Recognised by Ubuntu 13.04

Hello friends!

I have an iPod Classic (120Gb), and everything was working fine a couple of months ago. Mysteriously, when I plug the device in my pc it is not recognised by the OS any more. I'm using Ubuntu 13.04. Whilst the iPod charges normally when plugged into the USB, I cannot access its library with any music software. Any ideas?

Thanks a million!