cannot restore corrupted iPod - busy

All my music dissapeared on my ipod. when i connect to my mac, and attempt to sync with itunes, I get an error message stating that the ipod is corrupted. When i attempt to restore, i get an error message stating that the ipod is busy. I have updated everything, tried different usb ports, and different user accounts on my mac, but i get the same error messages.

Hope someone can help. Thank you!