I just purchased "Wireless Handwheel USB MPG Pendant for CNC Mach 3/4 axis". After I installed Plugin in the folder, MACH3 became very unstable... Every time it triggers error "ART CODE 9991".
I uninstalled plugin and everything became again normal. I tried to find the answer, but it looks like - there is no answer. I updated MACH3 with newest version R3.043.066 and I updated my Windows XP - NO HELP!
Does anybody know the solution for this matterr? 
Thanks

New experience!
Because my computer is not connected to internet - I didn't update my Microsoft XP for a long time. It took me almost a half day to update it ( there were 57 new updates) and I mentioned before, I updated it to newest version of MACH3. Now ( so far), everything works fine.

The same happens to me using XHC chinese pendant.