Wrong file loading from Memory Card?? HELP!

Hi there, I am knew to MPC1000 world but enjoying so far, but can;t seem to load standard .WAV files dragged from my Mac to my Flash card when loaded into MPC???

The files are there in the directory no problems but when i load it, it says "wrong file" does anyone know what this is?

The files size are about 1MB so i have plenty of space left.

Thx again.

Yo lampdog, thx a million for the reply, so ya saying ALL files you put into the MPC must be 44khz 16 bit...right?

Thx