I'm using one of the older versions of TrackIr so I don't know if your software allows you to see virtual heads or the actual dots the system is using to determine head position.
EVERY problem I've had with TrackIr has had to do with the sensor not seeing well enough. Either I was too far away, or I had something else in the sensor's field of view confusing it. Overhead light, mirror, reflective vest. After checking everything else, I look at what the sensor sees, and viola! There's the problem. Table light reflecting off a mirror, or some such nonsense.
Hope this helps.