changed the shader to 2.0 and no joy

i can`t figure why this will not work. is it possible to get atmosperic efects useing ffe`s?
i don't know whats wrong with it, could be your card driver? this is not very complex shader, and my card is a weak and it goes fine.
Sorry, maybe its what slin says, dirty code. Maybe he could help, he seams very exprt in shaders.