It's been awhile since i did any work on skins but your missing a WHOLE lot.
If the file i downloaded is what your putting in your main that there is totally wrong.
use pakscape to make the file a pk3
http://homepage.ntlworld.com/zagz/pakscape.zip
I'm not sure the folder path you have in that .zip is right either. I'm sure when Scorpion replies he'll be able to help you much more.
Download a skin for the Axis nades and tear it apart seeing how it was made and set up. That helped me out alot.
good luck