Nah, I know why!
The XLM is iTune's is way of basically storing the playlist information. The actual music isn't stored there. That's why the file is so small, only about 20Kb.
Look in the preferences of iTunes to find out where your music is being ripped to. Then go to that location and save it to the USB Drive.
It should be in My Music.
EDIT: Thought I'd try out my newly acquired Mod abilities and put this thread in the right forum
