Finally had a chance to dig into the issue again.

Indeed selecting run as admin made it work, but no matter what even setting the STOM^.exe util to always run as admin it wouldn't seem to stick. Again if I right clicked and selected run as admin it would then process and after I dismissed the error dialog from RB the processed file was loaded into RB just fine.

What finally resolved it was to set RealBand 2011 to always run as admin, but of course windoze 10 always insists on asking me if I want to allow RealBand to make changes when I start it up now. Have to see if I can track down where to tell Windoze to not nag me. It's an annoyance, but at least I can now load .mpg files in RB on the notebook again.

Note this is much easier on Linux. That is to set user (and other) permissions on an application (when needed).

Another rainy day project will be to see if I can get RB configured under Wine to access my external MIDI synth module over USB. If I can do that, and if it runs well, then I'll just run it on Linux under Wine in the future.