Why won't my tweening script work?

It's supposed to go from the left to the right at the top left corner of the screen then when the X is clicked it should go back out of the screen. What's wrong?

function open()
wait(1)
script.Parent.Frame:TweenPosition(UDim2.new(0,0,0,0),"In","Quad",1)
script.Parent.Frame.Button.Text = "Welcome to SIDRAT Laboratories, "..script.Parent.Parent.Parent.Name.."!"
end
open()
function close()
script.Parent.Frame:TweenPosition(UDim2.new(0,-500,0,0),"Out","Quad",1)
wait(3)
script.Parent:Destroy()
end

script.Parent.Frame.ButtonX.MouseButton1Down:connect(close)

It should be

script.Parent.Frame:TweenPosition(UDim2.new(0,0,0,0),"In","Quad",1)