Open the 3DxWare control panel from the desktop or control panel icon and select the "Calibrate" button. Do not touch the SP during this process. That should quiet it down. If it doesn't, let us know. You can also just unplug the thing and reconnect it (also while not touching the SP).
I suggest you contact technical support. Perhaps your device needs to be replaced. Do you also have this continuous movement in the demos (e.g. Cube 3D Demo) without touching the device?