Are you using a shader for your terrain? If so, is it embedded into your terrain model file? I have experienced this issue before but only because...

1. My fog was set to a very low distance making everything dark. My fog_start and fog_end were incorrect numbers that I mistook for being correct.

2. My shader was not applied correctly in my script, I also believe that I saw this when embedding the shader into the model itself in MED. To get around this I had to manually apply the shader in the script itself.

3. The shader you are using for this terrain is not getting valid input. If the shader is multi tex terrain and you don't have exact values, you can either get a white or a black output.

4. Like the post above, incorrect image properties can show a different output in the game engine. If you are using BMP files, make sure they are 24 bit, if they are TGA files, make sure they are 32 bit. All images should really be a power of 2 (512X512, 1024X1024, etc)

If it would help, I wouldn't mind taking a look at it if you want to send it my way. Compile it all up and let me see what I can find on my end, but only if you want. garrett@garrettwademan.com