Npc code spawning

Hey guys. Im getting a error if you can help me make this poor little combine shoot at me. Thanks!



function NPCSpawns()
	local Combine1 = ents.Create("npc_combine_s")
	Combine1:SetPos( Vector (1592.581299, -1632.102539, -58.592445) )
	Combine1:Give("weapon_ar2")
	Combine1:Spawn()
	
	timer.Simple( 1, function() StopNpcSpawns() end )
end

function StartNPCSpawns()
	NPCSpawns()
end
hook.Add("InitPostEntity", "StartNPCSpawns", StartNPCSpawns)

function StopNpcSpawns()
	print("Npcs have been spawned.")
end