[musicman691]

Make sure the MIDI channel output from PT and the MIDI channel input on the Phatty are set to the same channel (you have a choice of 1 through 16). I do something similar to you for my Moog Voyage rackmount. Here's my chain:
PT MIDI track set to the port and channel on my MIDI interface (MOTU MIDI Timepiece AVUSB) my Voyager is set to. The MIDI track input is set to receive MIDI from my controller keyboard (Yamaha Motif 7).

PT Aux track input is set to the line input from my 11 Rack which is my audio interface. The audio out of the Voyager is connected to the line input on the 11 Rack. I use an Aux track for this so I can hear what's being played.

When I want to render the MIDI I recorded into the PT MIDI track I go to the Aux track and select 'new track' from the output field menu and create an audio track. The output from the aux track automatically gos to the input of the newly created audio track without having to mess about with bus routing. I then record enable the audio track, hit f12 on the keyboard and the audio from the Voyager is rendered. Of course I make sure the levels aren't overdriving the audio track by lowering the level of the Voyager coming into the 11Rack.