Error Help Please!

So when my Npc's attack me I get this error-
Error running Lua task: [4D7F3D00012EA902] CombatWrapAPI:82: attempt to call a nil value (method 'IsA')
Tick function has stopped running. Script: "CrossContextCaller", Asset ID: FF24C1B0081B36FC

I cannot figure it out. They don't do damage and I cant damage them. Prob a simple fix and I am just being a bit slow. But please help!

Likely due to your weapon not being setup correct.

I would take a look at the NPC Kit tutorials from the creator of it.