iPod classic disk cannot be read/written.

Trying to sync iTunes collection to a new iPod classic. It used to work fine on an iPod Touch. Now, however, iTunes syncs some, but not all, of the music files. I get two error messages. One says that particular tracks cannot be synced. The second says that the iPod disk can't be read or written to. Using Windows.

Any advice from the community would be much appreciated.