Why does the error tell me i would attempt to index nil with 'Parent'?

I am trying to make a script that has a camera in the world and copys/removes the folder in the viewportframe but it keeps on erroring if it tries to change the parent of a cloned part

Players.EnderPowerHD.PlayerGui.SurfaceGui.LocalScript:20: attempt to index nil with 'Parent'

/\ The Error

/ My Local Script

game.Workspace:WaitForChild(game.Players.LocalPlayer.Name)

local camera = Instance.new("Camera")
camera.CameraType = Enum.CameraType.Scriptable
camera.CFrame = game.Workspace.Cam.CFrame
script.Parent.ViewportFrame.CurrentCamera = camera

while true do
	script.Parent.ViewportFrame.Folder:Destroy()
	local folder = Instance.new("Folder")
	folder.Parent = script.Parent.ViewportFrame
	
	local world = game.Workspace:GetChildren()
	
	for i = 1,#world do
		if world[i]:IsA("Terrain") == false then
			if world[i]:IsA("Camera") == false then
				if world[i] ~= nil then
					local part = world[i]:Clone()
					part.Parent = folder
				end
			end
		end
	end
	
	wait(1)
	
end

Why are you doing a for loop on this?

 for i = 1,#world do
	        if world[i]:IsA("Terrain") == false then
	            if world[i]:IsA("Camera") == false then
	                if world[i] ~= nil then
	                    local part = world[i]:Clone()
	                    part.Parent = folder
                end
            end
	        end
	    end

Here a fixed line of your code

for i, Object in pairs(world) do
	if Object.ClassName ~= "Terrain" and Object.ClassName ~= "Camera" then
		if Object ~= nil then
			local Cloned = Object:Clone()
			Cloned.Parent = folder
		end
	end
end

Found the problem myselfe i was copying Player Models which are not Archivable i had to turn Archivable on before i copy them