Welcome to the Board.
Never heard of this machine before but will try to help. How does it stitch using manually? If that is ok, I would suggest checking that the encoder wheels sit firmly on the tracks and make sure they are turning easily - you may need to use a drop of oil if they don't. Perhaps you will need a new regulator kit. Do check yahoo and facebook for groups who have this machine.
I have a Tin Lizzie with the older regulator and have had nothing but trouble with the wheels not turning as they should. Also I have a dial to adjust the speed I can move the machine. If you also have this, try turning it up to a higher speed, as it gets harder to push around on a low speed.
Good luck.