ipod 4th gen will not sync

my ipod 4th gen will not sync. My Mac is up to date, so is itunes, and my ipod. I've done factory restores and it will not sync. i select my music library, and it shows audio on the info bar at the bottom and the sync button is not ghosted. i click sync, it shows a progress bar up at the top for about 1-2 seconds then disappears all together like it's done. only there is no music on my ipod, and the sync button is now ghosted and it won't let me proceed further. ????

OSX-10.6.8 / iTunes-11.4 / ipod ios-6.1.6