Problems with effects.

[Muad'Dib]

S!
I'm trying to made a desert scene with 2 M1A1.
I'm a noobie, so the scene I've made with the help of the desert scene tutorial,
the M1 I've got in the Gunpoint.
The problems begins when I try to put some smoke and dirt effects in the M1's. I created a Atmospheric Aparatus and added volume fog to it, but when I rendered the sun glow becomes black and I couldn't find why.
Please a need serious help.