Midas M32R as control surface

I'm trying to make Reaper talk to my M32R for control data. It works fine as a Mackie Control Universal device with Ableton, but whenever I try to set it up as a control surface in Reaper, it pops a dialog that says "Control Surface: Error opening MIDI inputs and outputs". Where am I going wrong? Has anyone done this successfully before?

RE: mackie protocol, the screen on the device has options on the remote tab of the setup screen for Mackie MCU, Mackie HUI, and Generic CC. I assume the generic cc is the 7 bit midi you're talking about. MCU works fine in Ableton, but none of the options seem to be able to connect to Reaper. If generic CC will get me basic transport controls on the assignable button section, I'll be happy, as I'm mostly using this rig for live multitrack recording. Any thoughts on where I'm going wrong on the MIDI In and Out? Its connected via USB.

I don't know this mixer, but on the old M32, you have in the prefs an option to have the midi thru usb.