That error would definitely suggest that the NUITRACK_HOME environment variable is not set correctly
Try opening a command window (cmd.com) and typing echo %NUITRACK_HOME%
Make sure the value points correctly to the root of your nuitrack folder path c:\Nuitrack or something like that.
Also maybe make sure that the environment variable is set to entire system - not just you - and further make sure you reboot after setting the value and check it again after reboot in cmd.com window.
Westa