Here is the trick:
Using REGEDT32, locate the Discworld Noir registry key at "HKEY_LOCAL_MACHINE\SOFTWARE\Perfect Entertainment\Discworld Noir". Under it there should be a value called "Start Windowed", which is set to "No" by default. Change it to "Yes".
Now, when you start up the game it runs in a window and looks like crap (because it's expecting 16-bit color mode). Press Alt-Enter to change into full-screen mode. THEN THE GAME LOOKS FINE, AND IT NO LONGER CRASHES!!!
I truly thought this was a miracle
I am also using the 1999 3CD Best of Infogrames version; a full install; and I'm running the game from the install directory.