Vicon plug-in

[dudey12]

I'm trying to use the vicon plug-in to access tracking data that vicon is spitting out.
I'm using the code provided in the example: simple.py

import viz

viz.go()

#Add a grounds
viz.add('tut_ground.wrl')

#The number of markers to connect to
NUM_MARKERS = 1

#Specify the IP address of the Vicon server. Default port is 800.
#If you wanted to specify port 803, you would do the following:
#PORT_VICON = '128.2.4.78:803'
PORT_VICON = '128.2.4.78'

#Add the specified number of markers
for x in range(NUM_MARKERS):
#Add a vicon marker
marker = viz.add('vicon.dls')
#Add a 3d ball to represent the marker
ball = viz.add('white_ball.wrl')
#Link the 3d ball to the marker
ball.link(marker)

#Move the viewpoint back 8 meters
viz.move(0,0,-8)


I'm finding that I'm only able to add two markers. The code works perfectly for two markers but if a third or fourth marker is added, I get an error message that says that the maximum number of markers has been reached.

Any help would be greatly appreciated!