Ipod- disk could not be read from or written to

i have just received a replacement ipod from apple, the first one i got would only load a ceratin amount (very small size onto an 80gb) of songs, would stop at bruce springsteen (!) and then a message would pop up on my macbook screen - 'error- disk could not be read from or written to'. I have the same problem with this one! i have talked to an apple call operator (not sure if she was technically competant- nice though) and she brought me through a few steps (is your software up-to-date) etc etc, nothing worked, dont think the same suggestions would work this time.any suggestions????