no smoke blender 2.55

hello im trying a basic smoke simulation. in the 3d view everything seems to be simulating fine. i have my domain and particle system, voxel data texture, volume material at zero density. I dont get any smoke in my rendered view. why?

here are some screenshots

3d view

rendered view

hy,


http://www.blenderguru.com/introduction-to-smoke-simulation/

got 'em?