the drives don't need to mounted read-write. you should check the size of the ds2b1.mp3. It should be 544539 bytes big. the shell script does an ls (list) of all installed FIDs. I think there are too much arguments to ls.
How many songs have you got on your empeg?
Shall change the ls command to :

ls -l /drive0 /drive1

Frank van Gestel