Script gives error when I plug in a variable into the function? [unanswered]

So this is my lightning script for my game and for some reason it stopped working at the zap function when I try to do bolt()

function bolt(pos)
			local CF = CFrame.new(workspace.Cloud.Position, pos) -- error
			local sound = script.StrikeSound:clone()
			sound.Volume = 1
			sound.Name = "Temp"..sound.Name
			sound.Parent = script
			game.Debris:AddItem(sound,10)
			for strike = 1, 8 do
			local lastPos = CF.p
				local Parts = 7
				local Arc = 20
				game.Lighting.Ambient = script.Flash.Value
				for i = 1, Parts do
					local targpoint = CF.p + ((CF.lookVector*((CF.p-pos).magnitude/Parts))*i) + Vector3.new(math.random(-Arc,Arc),math.random(-Arc,Arc),math.random(-Arc,Arc)) -- eror
					if i == Parts then
						targpoint = pos
					end
					local s = Instance.new("Part")
					s.formFactor = 0
					s.Size = Vector3.new(1,1,math.floor((lastPos-targpoint).magnitude))
					s.CFrame = CFrame.new((lastPos+targpoint)/2,targpoint)
					s.BrickColor = BrickColor.new("Bright yellow")
					s.Anchored = true
					s.CanCollide = false
					local m = Instance.new("BlockMesh")
					m.Scale = Vector3.new(5,5,1)
					m.Parent = s
					local sc = script.BoltScript:clone()
					print'incoming lightning'
					sc.Disabled = false
					sc.Parent = s
					s.Parent = workspace
					lastPos = targpoint
					
				end
				wait(0.07)
				game.Lighting.Ambient = script.Storm.Value
				wait(0.01)
			end
		end

FindFirstChild expects a string, chosen is an object. Use chosen.Name instead of just chosen on line 53.