It looks like your code is just getting a handle to VRPN sensor 0, which corresponds to marker 1 in PPT Studio.
If you add the following code to your script do you see the axis model move with the wand:
Code:
import vizshape
axis =vizshape.addAxes(length=0.1)
wandTracker = vrpn.addTracker('PPT0@WORLDVIZ-PC',1)
viz.link(wandTracker,axis)