iPod Music won't copy to iPod in iTunes 8

My friend is trying to copy music over to her 3rd gen iPod. It has worked fine previously, and will work if windows explorer is open by copying to the ipod. If she just uses itunes though, it won't copy over and there are no error messages. Any idea what could be causing this and what she can do to fix it? Thanks.

Downgrading to 7.7 was the only way to get it working, not that it seems anyone cared.