Ipod won't sync, missing file

My ipod (5thG, 80gb) keeps getting to about 600 songs when syncing and then stopping and saying a file can't be read or is missing. I've tried all the steps, manual loading and different songs to check if it is dodgy files messing about and nothing has worked.

Other people seem to have had similar problems with few solutions so far and I have tried those that have been suggested to no avail.

Any advice?