I have a Monster Mill 3. I was struggling a bit to get it to hold a gap, and then to get the rollers to spin, then in some sort of desperation I loosened a couple bolts holding it to the cart. Voila! Turned out that I didn't quite have things perfectly aligned, and tightening them TIGHT caused a slight misalignment of the mill.
So, check on that if all the above isn't working for you, or isn't a permanent fix.