Marty - Thank you so much for posting your video. It solved the problem.
I'm embarrassed to say what the problem was, but I know it's important to let you all know how dumb I feel.
The first hold up that I was having was because of the missing instructions for changing the parameters. That was solved very early in this thread.
The problem that I was having with the MDI not accepting my block was because I was entering the command: M3 S750 and pressing 'enter' - not entring the blocking and pressing the cycle start. On the machine at work, the block has to be 'entered' before cycle start is pressed.... and that is what i ASSUMED was common... obviously it is not. Without seeing it the video, I would have continued to press 'Enter' after the block and continued to get the error.
It's a lesson for me in assumptions and following instructions.
Thank you all for all your effort in fixing this. Everything is working fine now and I will start with the wiring of the real components.
Marty - I know posting that video took you time and I appreciate it more than I can say. There are three important parameters that need to be changed that are not in the instructions, so a technical builtin would probably be a good addition for the Centroid team - it would have solved my initial frustration (although I may have still been stuck on the 'enter' vs 'cycle start')

-jason (forever humbled and embarrassed)