haptic device problem

[guof6570969]

hi all
when I use haptic device,my output show me as below:
** ERROR: Failed to initialize haptic device
** ERROR: Failed to initialize modifier hd2.dlm
Traceback (most recent call last):
File "<string>", line 11, in ?
File "ConstantEffect.py", line 25, in ?
ce = hd.ConstantEffect(dir=[0,0,-1],mag=1)
File "C:\Program Files\WorldViz\Vizard30\python\hd.py", line 353, in __init__
Effect.__init__(self,EFFECT_CONSTANT,**kw)
File "C:\Program Files\WorldViz\Vizard30\python\hd.py", line 305, in __init__
self.id = _hd_.get()[0]
IndexError: list index out of range

I just run the demo!