MPC can't read my disk

I have music and sequences that I recorded on an MPC 1000, on the Operating system which was updated in 2005-2006 (JJ. Which version not sure), stored on a compact flash disk. I tried to use a friend's MPC and it couldn't read the disk. I saw the data through his computer though. What could be the reasoning behind his MPC not being able to read my disk? Could it be due to the different operating systems?

Can a poor brother get some help?