Loss of Program Sounds when changing Sequences

This is for MPC 3000. I've been encountering an unusual problem when changing sequences in the MAIN SCREEN window. This is the first time I've had this problem. When I change from sequence 1 to 2, for example, I suddently lose all my program sounds. The pads lose all their sounds and I have to load the program again. Then I'll go back, and as long as I leave the current sequence selected, and press play, everything plays back fine. But as soon as I go from one sequence to another, I lose all my sounds again.

Does anybody know what my problem may be, or has anyone else encountered this issue?

In each sequence.

Ensure that:

a) the output selection it for DRUMS and not MIDI
b) the DRUM program number is selected.
c) the TRK ON/OFF parameter is to ON.

Rohan