A few simple checks first:
You have enabled MPG #1
You have ports set on 2 and A and B set to 11,12
you set the counts to around 4 to start or did you use mpg setup dialog?
When you hit the Tab key, and the MPG Jog fly out comes out, is "Jogging enabled"?
You have to hit the "control jog" button and have it cycle from continous, to step and finally make sure you are on MPG
Look at your MPG axis selector lights, make sure you have the correct LED for the axis you want.
Make sure the power, ground and A,B leads all goto you Break out board, and you measure 5v on the power of the MPG.
scott