Mod Menus dont work...

Everytime i use any mod menu it gives me this error
Does anyone know how to fix...

Are you playing in a private match?

you will need to type developer 0 and developer_script 0 into the console to avoid annoying popups in game.

I see you're using a zombies menu. With that being said, you MUST play in private match or you will always get this error. Treyarch has unfortunately patched menus in multiplayer.