script.Parent is nil???

I have no idea wtf is happening, this code outputs an error ( https://gyazo.com/0168b4b486c548001409a959119b0233 ) saying at line 27:

itemgui.Parent = script.Parent

that script.Parent is nil.. I don't know what is means because the script does have a parent: https://gyazo.com/e82f25bb51c3c57f9998a03b86e2036a Full code:

wait(2)

local db = false

script.Parent.Changed:connect(function(val)
    if db == false then
        db = true
        if val == "Visible" then
            if script.Parent.Visible == true then
                local itemstoload = game.ServerStorage.DATA_STORAGE:FindFirstChild(script.Parent.Parent.Parent.Parent.Name):FindFirstChild("Items"):GetChildren()
                for i,v in pairs (script.Parent:GetChildren()) do
                    if v.Name ~= "Script" and v.Name ~= "EmptyItemGui" and v.Name ~= "UndoButton" then
                        v:Destroy()
                    end
                end
                local amountofitems = 0
                for i,v in pairs (itemstoload) do
                    local itemgui = game.ServerStorage.EmptyItemGui:Clone()
                    local row = math.floor(i/3)
                    itemgui.Position = UDim2.new(0,((i - (row * 3)) + 10),0,((row * 130) + 10))
                    itemgui.Text = v.Value
                    itemgui.Script.Disabled = false
                    itemgui.Parent = script.Parent
                    amountofitems = i
                end
                script.Parent.CanvasSize = UDim2.new(0, 0, math.floor(amountofitems/6), 0)
            end
        end
        db = false
    end
end)