You installed the files in the wrong place. When you unpack the archive with winrar, copy the main folder, meaning the folder that has the materials and models folder inside it to!
C:\Program Files (x86)\Steam\steamapps\common\GarrysMod\garrysmod\addons
Remove any other files you installed in the wrong place. It might conflict. And get this as well.
http://steamcommunity.com/sharedfiles/f ... =104603291
It will gather any addons you install in a folder called Legacy Addon for easy find. See screenshot. Hope this helps you sort it out.