Problems with restoring iPod: unknown error 1430

I bought a used 5G iPod nano. Everything was ok, until I plugged it to my computer (a macbook). Than I had to restore it but an unknown error 1430 appeared. So far I have tried everything: Apple tips on their website, different tips on the web, even erasing iPod using disk utility.

I really don't know, what to do. Do you have any idea?