That didn't work any better.
I uninstalled Mach 3, ran a reg cleaner which deleted several Mach 3 keys, reinstalled Mach 3, installed the ST plugin and started Mach 3.
i got the same error messages as before. It tells me that the Galil ST DLL is defective. I am running a new installation of XP with no internet connection and I have disabled all unnecessary features that I can think of, such as the firewall, auto-updating etc..
The only other software that I have installed is Galil suite and the reg cleaner.