While there might be something picky, it would probably help if you say your OS and blender version, build no. If it’s anything different than 2.49, that is.
I did try this on blender 262.3 both win and linux. On linux, it refused to allow me to choose 4th output of nodes, did repeat one, like in some comment on tutorial page. On win box it did all nicely, however while blender versions are the same, actual build numbers likely are different. Again, i might have just learned “by hands” and am missing some significant “don’t do this” part.
In short - it works if you closely follow tutorial and it might show unexpected behaviour if done a bit differently. Start over in a new file.