Congratulations. You have recieved the private Garrys Mod 004 gold members beta {SH-LEAK}.
This file is private to only a few people.

Installation:
After extraction, there should be a folder called gmod_gold004{sh-leak}.
Open that folder and take the file gmod_gold out and place it in your Steamapps/SourceMods folder.
You should now be able to play the mod.