Script return "attempt to index a nil value" after every death?

Hi guys. This walk script for a Zombie keeps returning the following error right after it's death. It annoys me because nothing is wrong with the code.

20:18:30.178 - Workspace.Lightning Zombie.walk:33: attempt to index a nil value 20:18:30.181 - Stack Begin 20:18:30.182 - Script 'Workspace.Lightning Zombie.walk', Line 33 20:18:30.183 - Stack End

local larm = script.Parent:FindFirstChild("Left Arm")
local rarm = script.Parent:FindFirstChild("Right Arm")
local torso = script.Parent:FindFirstChild("Torso")
function findNearestTorso(pos)
	local list = game.Workspace:children()
	local torso = false
	local dist = 1000
	local temp = nil
	local human = nil
	local temp2 = nil
	for x = 1, #list do
		temp2 = list[x]
		if (temp2.className == "Model") and (temp2 ~= script.Parent) then
			temp = temp2:findFirstChild("Right Arm")
			human = temp2:findFirstChild("Humanoid")
			Zombie = temp2:FindFirstChild("Zombie")
			if (temp ~= nil) and (human ~= nil) and (human.Health > 0) and Zombie == nil then
				if (temp.Position - pos).magnitude < dist then
					torso = temp
					dist = (temp.Position - pos).magnitude
				end
			end
		end
	end
	return torso
end




while torso ~= nil do
	wait()
	local target = findNearestTorso(script.Parent:FindFirstChild("Torso").Position) --Problem Here
	if target ~= false and target ~= nil then
		script.Parent.Humanoid:MoveTo(target.Position, target)
	end
end