Vizard uses a special build of the isense.dll that is supposed to fix some problems. Can you try downloading the 4.0.4 version of isense.dll located at
http://www.isense.com/support.aspx?id=373? Replace the existing isense.dll file in the Vizard/bin directory with the downloaded version and see if that fixes the problem. If so, we might need to rollback the included driver that comes with Vizard until InterSense provides a more stable one.