I've followed the advise given by Apple but it still doesn't sync it.
http://support.apple.com/kb/HT1210
this happens now very often and even after
resetting the iPod the error continues to appear.
Did you restore it?
If yes, and supposing the reason is some corrupted file (s) and supposing you cannot find which ones to blame, why don't you try with a small set of new files for some days to see if the problem stops?
The FILE playing in itunes does not guarantee it will correctly play in the ipod.
Another option is to try a second computer, if you have access to one (after you have restored the ipod). This can help ruling out a nasty program misbehaving in your current windows installation.