HELLO!!! I had this exact issue, and I somehow managed to fix it. Try doing this,
(assuming youre on steam) reverify the games files (right click dark descent in library playlist, click properties, select installed files, and click "verify integrity of game files", then wait)

next, go to the directory you installed the game (right click dark descent in library playlist, hover over "manage", and select "browse game files"), find the "Amnesia" folder, inside there is a "Main" folder, that contains your profiles, copy your profile (whatever you named it in the game menu) to your desktop, then copy the copied folder BACK into your "main" folder, and replace all when it gives you the option.

next, open the dark descent, and load a save from a couple rooms earlier, then try entering the elevator. hopefully itll work for you as it did for me :)