TweenService:Create failed because Instance is null?

I have a simple tween script for a door I'm working on and it's giving me an error, but I do not know why. Any help is appreciated!

TweenService = game:GetService("TweenService")

script.Parent.Open.Changed:Connect(function()
    if script.Parent.Lockdown.Value == false then
        if script.Parent.Open.Value == true then
            local Info = TweenInfo.new(0.1, Enum.EasingStyle.Quad, Enum.EasingDirection.InOut, 0, false, 0)
            TweenService:Create(script.Parent.Door.PrimaryPart, Info, {CFrame = script.Parent.Positions.Opened.CFrame}):Play()
            script.Parent.Door.PrimaryPart.OpenClose:Play()

        elseif script.Parent.Open.Value == false then
            local Info = TweenInfo.new(11, Enum.EasingStyle.Bounce, Enum.EasingDirection.Out, 0, false, 0)
            TweenService:Create(script.Parent.Door.PrimaryPart, Info, {CFrame = script.Parent.Positions.Closed.CFrame}):Play()
            script.Parent.Door.PrimaryPart.OpenClose:Play()
            wait(0.8)

        elseif script.Parent.Lockdown.Value == true then
            if script.Parent.Open.Value == true then
                local Info = TweenInfo.new(0.01, Enum.EasingStyle.Quad, Enum.EasingDirection.InOut, 0, false, 0)
                TweenService:Create(script.Parent.Door.PrimaryPart, Info, {CFrame = script.Parent.Positions.Opened.CFrame}):Play()
                script.Parent.Door.PrimaryPart.OpenClose:Play()
                script.Parent.Lockdown.Value = false

            elseif script.Parent.Open.Value == false then
                local Info = TweenInfo.new(.1, Enum.EasingStyle.Bounce, Enum.EasingDirection.Out, 0, false, 0)
                TweenService:Create(script.Parent.Door.PrimaryPart, Info, {CFrame = script.Parent.Positions.Closed.CFrame}):Play()
                script.Parent.Door.PrimaryPart.EmergencyClose:Play()
                script.Parent.Lockdown.Value = false
                wait(0.8)

            end
        end 
    end 
end)