An Unknown Error Occurred (-50) when I was tried to sync my iPod what do i do

I am using a hp computer with windows visa. I went to iTunes and checked off all the music I wanted, pressed apply and it started to sync. When it went to step 2/6 saying preparing to sync iPod and after it said transferring purchased items to 'iPod' a pop up shows up and said- The iPod "iPod" cannot be synced. An unknown error occurred (-50). How do I fix this?