Argh Nisis, my sister bought her first cheap digital camera from them and threw it in the bin a day later.
It's definately supported in Paint Shop Pro
http://www.nisis.com/Products/GraphicTablets/G3FAQ.asp
try reinstalling the drivers from:
http://www.nisis.com/pub/USBTabletDrivers.exe
and look in the manual:
http://www.nisis.com/pub/USBGraphicT...ationGuide.pdf
to see if there's anything you need to do to get it working under third party software properly