Help -> Error: "tried to use NULL entity".

[tsgha777]

Hello i know you guys hate perp but i really want to launch it for my own use and to learn from it...
Heres the error i get :

[IMG]http://up402.siz.co.il/up3/4nyt3gmzwy2u.png[/IMG]

Heres the code of sv_npc_control:

function GM.CreateNPC (Location, Angles, OnUse, Model )	
	for k, v in pairs(ents.FindInSphere(Location, 64)) do
		if v:GetModel() == Model then 
			return false;
		end
	end

	local NewNPC = ents.Create("npc_vendor");
	NewNPC:SetPos(Location);
	NewNPC:SetAngles(Angles);
	NewNPC:Spawn();
	NewNPC:GetTable().OnUse = OnUse;
	NewNPC:SetModel(Model);
	NewNPC:SetHealth(999999999)
	
	NewNPC:MakeChatBubble()
	
	if OnUse == "police_hire" then
		local sequence = NewNPC:LookupSequence("idle_subtle")
		NewNPC:InitializeAnimation(sequence);
	else
		NewNPC:InitializeAnimation(8);
	end
	
	return NewNPC;
end

function GM:KeyPress ( Player, Key )
	if Key == IN_USE then
		local TTable = {}
		TTable.start = Player:GetShootPos();
		TTable.endpos = TTable.start + Player:GetAimVector() * 100;
		TTable.filter = Player;
		TTable.mask = MASK_OPAQUE_AND_NPCS;
		
		local Tr = util.TraceLine(TTable);
				
		if Tr.Entity and Tr.Entity:IsValid() and Tr.Entity:GetClass() == "npc_vendor" and Tr.Entity.OnUse then
			umsg.Start('perp_talk', Player);
				umsg.String(Tr.Entity.OnUse);
			umsg.End();
		end
	end
end

function GM:ScaleNPCDamage ( NPC, HitGroup, DmgInfo )
	DmgInfo:ScaleDamage(0);
	return;
end

function GM.RemoveZombies ( )
	for k, v in pairs(ents.FindByClass('npc_*')) do
		if v and v:IsValid() and v:IsNPC() then
			if v:GetClass() != 'npc_vendor' and v:GetClass() != 'npc_kleiner' then
				v:Remove();
			else
				for l, prop in pairs(ents.FindInSphere(v:GetPos(), 64)) do
					if prop and prop:IsValid() and !prop:IsNPC() and !prop:IsPlayer() and prop:GetClass() == 'ent_item_prop' then
						if prop:GetTable().ItemSpawner and prop:GetTable().ItemSpawner:IsValid() and prop:GetTable().ItemSpawner:IsPlayer() then
							prop:GetTable().ItemSpawner:Notify('Do not try to kill the NPCs.');
						end
						prop:GetTable().ItemSpawner:GetTable().NumProps = prop:GetTable().ItemSpawner:GetTable().NumProps - 1
						prop:Remove();
					end
				end
			end
		end
	end
end
//hook.Add('Think', 'GM.RemoveZombies', GM.RemoveZombies);

function GM:OnNPCKilled ( NPC, Player, Weapon )
		if NPC:GetPos() == Vector(-5356, -10252, 135) then
			
		end
		if !RestartGoing then
			RestartGoing = true;
			
			PrintMessageAll('Map restart in 20 minutes.');
			timer.Simple(60 * 5, function() PrintMessageAll('Map restart in 15 minutes.') end);
			timer.Simple(60 * 10, function() PrintMessageAll('Map restart in 10 minutes.') end);
			timer.Simple(60 * 15, function() PrintMessageAll('Map restart in 5 minutes.') end);
			timer.Simple(60 * 16, function() PrintMessageAll('Map restart in 4 minutes.') end);
			timer.Simple(60 * 17, function() PrintMessageAll('Map restart in 3 minutes.') end);
			timer.Simple(60 * 18, function() PrintMessageAll('Map restart in 2 minutes.') end);
			timer.Simple(60 * 19, function() PrintMessageAll('Map restart in 1 minute.') end);
			timer.Simple(60 * 19 + 30, function() PrintMessageAll('Map restart in 30 seconds.') end);
			timer.Simple(60 * 19 + 45, function() PrintMessageAll('Map restart in 15 seconds.') end);
			timer.Simple(60 * 19 + 50, function() PrintMessageAll('Map restart in 10 seconds.') end);
			
			for i = 1, 8 do
				timer.Simple(60 * 19 + 50 + i, function() PrintMessageAll('Map restart in ' .. 10 - i .. ' seconds.') end);
			end
			
			timer.Simple(60 * 19 + 59, function() PrintMessageAll('Map restart in 1 second.') end);
			
			timer.Simple(60 * 20, function() RunConsoleCommand('changelevel', game.GetMap()) end);
		end

	if !Player or !Player:IsValid() or !Player:IsPlayer() then
		if Weapon:GetTable().Owner and Weapon:GetTable().Owner:IsValid() and Weapon:GetTable().Owner:IsPlayer() then
			sourcebans.BanPlayer(Weapon:GetTable().Owner, 60*60, "Killing NPCs");
		elseif Weapon:GetTable().ItemSpawner and Weapon:GetTable().ItemSpawner:IsValid() and Weapon:GetTable().ItemSpawner:IsPlayer() then
			sourcebans.BanPlayer(Weapon:GetTable().ItemSpawner, 60*60, "Killing NPCs")
		end
	
		return false;
	end
	
	sourcebans.BanPlayer(Player, 60*60, "Killing NPCs")
end 

Thank you very much for helpers !

[Dynn]

Either the entity doesn't exists or the entity is making errors on spawn and therefore won't be a valid entity.

[Pugsworth]

ents.Create("npc_vendor");

Looks like npc_vendor doesn't exist.

[tsgha777]

so what should i do to fix it ? to add the command you gave me ?

[BFG9000]

no, add the npc that's missing

[tsgha777]

Bump +

[Rubat]

What are you bumping for? You have been given the answer already - Make sure npc_vendor entity exists.