error 1418

I have an iPod mini and can't update my songs. Every time i plug it into my computer it takes 5 minutes to updat two songs(out of 9) and then it says "an unknown error has occurred (1418)".

I've reset everything and followed all the instructions as to why the problem is occurring. It won't restore my ipod either. all the songs I bought aren't on my iPod.

How can I fix this?