Ok an update...
Yes, I am definitely running mgalaxy 4.1
My OS is Windows XP service pack 2.
I updated ALL software updates/frame networks, etc.
I reinstalled mgalaxy. I redid all the paths.
NOTHING CHANGED.
So again, MAME and SNES emulators work 100% with mgalaxy.
Any NES emulator I try (I have them all downloaded now) shows all my roms, but when I click on one, I get the "sands of time" icon... nothing happens for about a minute, and then the "encountered an error, need to shut down" message comes up.
I'd love to have all emulators under a simple front-end, and mgalaxy has worked the best until this nes problem.