Can you start with a simple example and verify that you get the correct output?
Code:
import viz
viz.go()
#Add ARToolkit extension
ar = viz.add('artoolkit.dle')
#Create camera using first available webcam
camera = ar.addWebCamera(window=None)
#Create a matrix marker with the specified id
marker = camera.addMatrixMarker(0,width=1000)
#Add logo model
logo = viz.add('logo.ive')
#Link logo model to marker sensor
viz.link(marker,logo)