Tried it before trying the SSBump Generator but it's a pain in the butt to use and it did'nt work.So you didn't use SSbump generator? You better use that instead of commandline generation, because it's way easier and it gives you a preview window.
It was complicated for me too, but since I learned it's sort of a routine to create a normal texture. The only problem is creating lots of textures.
Oh Muzz, always complaining about complicated stuff!