iPod touch Contents from my external HDD into my PC?

Hi,

I got a new laptop and I need to put all my songs back into iTunes for my iPod touch. Whenever I add them in, it works fine. However, when I safely remove the hard drive, iTunes says the songs have to be located. How do I copy over the contents of the external hard drive into my PC's? I tried just dragging it, but then it says 'G: can't be found' or something...

Thanks.

It was working and then it failed because of an error or the names were too long?