burn texture is a texture that is like a glow map but it slowly fades out over a table based time.
I'm not sure if the backface texture even works anymore, I may have removed it, it was a texture you would give to decals that would be applyed to faces pointed away from the impact site, so that on thin wings (or something) when you shot them there would still be a scorch mark on the other side, but a diferent texture, the idea being that it would look more realistic, like you were shooting holes through the wing.
you have to use textures with alpha, or the green transparency thing (only works in PCX I think though).
the white box thing, do you have mip-maping on, if so turn it off and tell me if this fixes the problem