iTunes says my iPod is corrupt. Why? It worked yesterday!!

I downloaded iTunes 8.2 to my laptop. I have been using my iPod (80Gb) in the car but decided to add some new music. iTunes said the iPod was corrupt and that I should restore it. As I wanted new music, I had no problem with wiping everything off. However, having restored, iTunes still says it is corrupt and now I cannot do anything with it; iTunes does not give me any download options at all - it continually tells me it is corrupt. So now I have nothing at all!

Is there a sensible fix for this? HELP!!!