welttraumhaendler: Kann dir leider nicht helfen, aber Teile deine Beobachtung.
Ich poste das mal hier rein, weil es dich ja offenbar auch interessiert.
Diese Antwort habe ich erhalten, das klingt zumindest schon mal einfacher, als die anderen Anweisungen:
1. Install the NewDark patch if you haven't already. The easiest way is to install TFix, which includes it and some other handy things.
2. Configure Thief Gold to use the built-in FM selector. The simplest way is to open cam_mod.ini in the game folder and change the line ";fm" underneath "; always start the FM Selector (if one is present)" by removing the semicolon in front. This will cause Thief Gold to automatically bring up the FM selector when the game is launched.
3. Also in the game folder, create a folder named "FMs" if there isn't already one. Then, create an appropriately-named folder inside that one that will hold the files for the FM.
4. Download the FM and unzip it to the folder that you created in step 3.
5. Start the game, the FM selector will pop up. The FM will have the same name as the folder you made in step 3. Select it and hit the "Play FM" button.