Looks like your in the wrong mode my friend.
in 'display00.wdl':
Code:
...
var video_depth = 16; // 16bit high-color
...
Have you tried setting this to 24 or 32. I had some similiar effects with skybox's.
Hope thats some help...
EDIT: Ok so I re-read your post, and see you already stated that you have tried the above

But that's what it looks like, maybe you have another definition in your code, resetting it back to 16? Sorry I should read more carefully! LOL