mpc2000xl external cd drive problem. Help appreciated.

I have aquired an external scsi cd dive. On SCSI channel #5 the mpc can see the cd drive, and can detect when a disk is inserted. The problem is that I cannot actually access any cd - regardless of format it seems. Even when i try the akai sound library for example.

When i am trying to access a cd, in the format parameter i get: "??????????" displayed.

I've read the manual tonnes and couldn't find any suggestions to resolve this. I am hoping someone on here has some experience of this?

Thanks
J