Gmod NPC error help

[LASER-----X]

I downloaded some half life 1 npc's. they used to work and attack my allies and me, but now when i spawn the they just stand there and i get this error:

entities/monster_base/init.lua:263: attempt to compare number with nil
entities/npc_mortarsynth/init.lua:293: attempt to call method 'ValidateRelationships' (a nil value)

i need your help plz!