User Tracker sample code problem

[gopinder verma]

hi,
       I am facing problem with  UserTracker sample code , before that i ran other sample codes they are working properly (Niviewer sample code );
       When i debugged UserTracker code
                 g_UserGenerator.GetSkeletonCap().IsTracking(aUsers[i])
      value is always zero , its not tracking object.
      Skeleton capability check is  passed in the code.
      In final output it only displays string "Looking for pose1 " or more in case of more users, no image.
                 In framework xnStartGeneratingAll()  function also not working .
     Is there any problem with the drivers or XML file settings.

Thanks and Regards,
Gopinder Verma