Well, it helps to read the documentation carefully when it exists. I was adding an extra parameter to the tween. You can delete this thread to reduce clutter.
http://www.stoneyphoto.com/runner/work/index.html
[-180 degrees, 180 degrees] => [-1.0, 1.0] for the ath attribute of the instance of the hotspot / plugin image
[-90 degrees, 90 degrees] => [-1.0, 1.0] for the atv attribute of the instance of the hotspot / plugin image