My iPod won't sync properly, I've tried everything! Please help!

It says gets to about 300-400 songs, freezes and says an unknown error occurred (-69). My iPod only has 30 songs on it now. I've formatted it, I've restored it, I've reinstalled iTunes and deleted all associated program files, but it still won't sync. I've had this problem for quite a while now, and I've done the same thing many times already. Can any one help me? 😟

(I have an iPod Classic 6th Gen 120gb)