vizconnect optotrak sensors to avatar

[shashkes]

I'm managing to connect to optotrak in a script by:

opto = viz.add('optotrak.dle',0,'192.168.1.1' )

body = opto.getBody(0) for m in opto.getBodyList():
ball = viz.add('white_ball.wrl',color=viz.RED,cache=viz.C ACHE_CLONE)

optolink1=viz.link(m,ball)

This provides me with two balls that follow the optotrak rigid bodies
but when I try to connect to optotrack through vizconnect with the same parameters I get:

** ERROR: Failed to load plug-in: 'optotrack.dle'
** WARNING: can't connect to Northern Digital Optotrack with index 0. It's likely that not enough sensors are connected.

Any idea why? My goal is to connect an avatar's hands to the optotrak sensors and use reverse kinematics, the simplest way seemed to be through vizconnect.
Is there any other way I could do this?
Thanks
Sarah