I just picked this game again for old time's sake :)

I have Flame's Mod 1.1 from way back in the day.

Does anyone know if it still works with the GoG version?

I tried installing it a few times, but it doesn't seem to have taken.

Any advice from the old Grognards on how to get such an awesome mod, from some such an awesome developer on how to get this gem running?

If you have installed the game in an uac protected folder, your OS is most likely the culprit.
May even need to uninstall it
before you place the game into a neutral folder outside \programs (x86) etc.

You can also have several installs with different mods by just using a clean install as base and copying it manually.

So just to make sure I follow:

Install the game in a directory outside the usual progrsmx86 whatever....

Then run the mod installer, and that may work?

I will give it a try.