Dave Smith Instruments SYNTHESIZERS

Hi

I'm trying to poly-chain my PEK to my desktop Evolver, and I'm not 
getting audio from the PEK.
I've followed the instructions as follows:

Connected a MIDI cable from the Poly Chain Out to the MIDI In of the Desktop
Set Poly Chain to 5 on the PEK
Connected the Mix Out of the PEK to the Audio In of the Desktop
Connected the audio out of the Desktop to my mixer
Set the MIDI Clock to"OUT" on the PEK
Set MIDI Clock to "IN"  on the desktop.

Software is 3.0 for the desktop.
I think it's 1.0 for the PEK (which I believe is up to date-not sure how 
to check this).

When I play the PEK, I'm only hearing the voice of the Desktop 
(basically, every fifth note that I play).
When I connect the PEK to it's own separate channel on the mixer, I hear 
all of the voices.

This works as a workaround, but I'd rather not use up 2 more channels on 
my mixer.

Is there something obvious that I'm doing wrong?

thanks,

Joe