This did the trick for me:
1. Download and install iExplorer http://www.macroplant.com/iexplorer/
2. Plug in device first, then open iExplorer
3. Delete the iPhone\Media\iTunes_Control folder (you may want to copy this, just in case)
4. Restart the iPhone / iPad
5. Start iTunes. Not restore iPhone from back up, select New iPhone (don’t worry, you will not lost apps or data on your iPhone doing this)
6. Add music manually with iTunes
Source: https://discussions.apple.com/thread/3979901?start=30&tstart=0
Solution by: https://discussions.apple.com/people/Galileo634