Quote: "when I test the game in the edditor, no problem. Doors work perfectly. But once I build the game all thats left are the frames of the doors, and the fake doors."
This is normally an indication that
all the required media did
not copy to the build- not a fault of the media itself but the engine's routine when in the build process. Doors use both a mesh and and entity reference. For example:
partmode0 = 0
meshname0 = meshbank\ww2\scenery\doors\door_g\door_g_frame.x
meshname1 = entitybank\Doomster Pack #1\Derelict Buildings\Doors\Door-1\Door-1 (Auto).fpe
I suspect the "entity" part (if referenced in the door's FPS file) is not getting copied to your build. All you have to do is find it and copy it manually to your build and the door will be there (if copied in the correct path structure).
One thing I will add- anytime there is something in a FPI, FPS, FPE with characters such as "#,&,%" in a defined path, the engine tends to ignore it which also can give the same result as the OP. We discovered this with the Dark Egypt Pack. If it is being used, you may have to manually copy missing media like we do.

There's no problem that can't be solved without applying a little scripting.