iPodtouch 4G does not synchronize correcttly with iTunes 10 and 11

Hello,

since I have my iPod 4G 64GB it does not synchronize correctly with iTunes versions 10 and 11 und Windows XP and 7:

Everything works fine, except for music where it tells me at the beginning of sychronizing that 4.500 songs will be synchronized (~27GB with ~32 free on the iPod) and in the end I have about 150 songs on it.

Does anybody know the problem and can help?

thank you & kind regards,

Kai