Ensure you are running Gmod on the x86-64 - Chromium + 64-bit binaries beta branch in Steam; otherwise, x64-specific cheats will not inject.
In the context of Garry's Mod, "friendly" often refers to the (requiring 10 friends to be online) or tools designed for server administration and creativity rather than malicious cheating. Tools for Friendly Gameplay: Guide :: So what's the deal with the 64bit branch? friendlyhack gmod x64