Hi 12strings,
I think that was the most helpful reply I've had with this!
I made a copy of the Mach4Mill profile and then enabled the PMDX on the Configure->Control->plugins tab. I hadn't thought of doing that. I don't get the message now. It's 1.30 am on a cold winter's night here in Melbourne, Australia, so I'm going to try this out in the morning. But I was getting that error all the time with the copy of the PMDX sample profile.
BTW, which profile would you recommend for a three axis CNC router? Mach4Mill or Mach4 Router?
Cheers!