Is your itune crashed before and then the cache still reading on that particular itune on the same PC?

I think for you to re-sync back to an empty PC, you gotta make sure you have the same path from your previous sync

odd thing, what mine is i synchronize between my pc and lappy

lappy needs to have same path and it works like charm after

It's easy, untick all that you don't want to sync.

Then file > add a file.

Select your video. It will be placed under movie.

In movie, select all unwatched to be synced.

When you sync, it will appear in video in your ipod

Try using winamp to sync your musics, it has a better performance