I cannot seem to Sync music to my iTouch. It comes up with an error message that says "The required disk cannot be found," after syncing around 10-30 songs. I took it to my friend's house and his computer sync'ed his music to my iTouch with no problem, but then when I took it home, the same problem occured, and again it Syncs ~10 songs then stops with an error message that says "The required disk cannot be found." I have tried different USB cables, but none of them worked. I also have iTunes 7.5, and have used this same library for my iPod Nano.