Node graphs not loading?

Hi, I downloaded an addon called Zombie Invasion that spawns NPCs to fight, ect., ect… The addon is not important. What is important is that it keep screaming in the console “No ai_nodes on map, NPCs will not spawn”. I have Garry’s Mod on another computer, with the same addons, and it works there, but not on this one… are there any console commands that disable node graphs? Please help! Thanks!

Just contact addon author for help.

It has nothing to do with the addon. I just said that. Something’s wrong in my configuration.

Well, good luck figuring it out then.