Alpha Appearing Black (Blender 2.5)

I’ve switched to the latest Blender and I’m having some problems with the textures on particle billboards not appearing correctly. I followed a tutorial on creating a tornado (http://www.youtube.com/watch?v=iLxdpqJDfgs&feature=related) and as far as I’m aware I selected every option the guy mentions.
As you can see in the picture I’m getting black edges around the circle where I should be getting transparency.

Any ideas?

Thanks

Attachments


Go into the texture settings and check the “premultiply” option.

Or activate transparency in material tab, set to ZERO, perhaps also alpha in ramp, and alpha in textures “influence” tab to ONE.

Can’t seem to find this option, could you explain where it is?

and delic all the options you said I already have set.

Thanks