Jetpack_monkey: There's maybe either something wrong with your models, or it's a bug in Gamestudio.

I suppose that you are using 6.40.5. Make sure that the background object is intransparent. Check the DDS texture. Only the DXT1 format is intransparent. All other formats have an alpha channel. As a test, apply a PCX or BMP texture that is certainly intransparent. If this does not solve the problem, please post again.