OMG FFS GAAAHHHHHHH!!! 
aaaYEP! It’s been Avast! all this time. … GAAHHHH
Disabled it, the GitHub version works just fine.
So I added the entire install folder of the GitHub version as an exception, re-enabled Avast!, and now … no more problem.
Good grief. ALL THIS TIME! All this headache and fighting with permissions and shit, and it was simply Avast! … damned anti-virus software can really be a PITA sometimes, but you pretty much NEED need it these days.
At any rate, situation remedied. All is back to normal.
Thanks for the help.
I should’ve thought to check Avast! quite early on in this fight. D’OH!
Now back to fighting with Inform itself to figure out why my “code” isn’t working as expected LOL