iTunes not reading iPod disk

After trying to import some mp3 files from a cd to iTunes, I connected my ipod to my computer to sync the music and during the sync process an error posted "ipod disk can't be read or written on". Another message appears when I try to eject my ipod reading,"ipod can't be ejected because some files are being used by another application".

I tried to restart, restore, re-install but keep getting the same message. I disconnect ipod when I shut down my mac, and it is still working, however I can't erase and restore it to get rid of what seems to be bad files in the disk.

S.Rashad