Rampy,
Any chance you are using advancemame coupled w/ optimouse that I told you about a few posts back? Just the other day, something similar happened to me. I loaded up tempest, and could spin in one direction perfectly, while the other direction only allowed me to move maybe 6 tempest 'spaces' and basically got stuck there. I couldn't spin past that point.
I thought maybe something got caught in the optics (wire, etc), but there was nothing there. It simply didn't make sense that a spinner could move fin in one direction, and lock up in another, after going only half way or so. To further add to the complexity, this didn't happen 100% of the time, either. Sometimes I'd boot up and it would work fine.
Changing to that dual mouse driver Oscar had on his website solved my problem, so far. Crap, you had the stutter problem with the dual mouse driver, right?
The other things I would try, which don't really seem to make much sense, but neither does this problem:
1) Switch your devices around... Whatever was in COM1, put in COM2, etc...
2) Go into advmame.rc and remove the unused axis from the spinner.
Hope one of these helps.