I made this script where when you click the window it moves. How can I fix this?

Okay, I made this script where when you click the window it moves upward or downward depending on it's position, and it doesn't work. The Output said "Unable to cast instance to CoordinateFrame"

Here is the script:

local part = script.Parent
local detector = part:WaitForChild("ClickDetector")
local opened = false
local one = script.Parent.Parent:WaitForChild("LerpTo1")
local two = script.Parent.Parent:WaitForChild("LerpTo2")

detector.MouseClick:Connect(function()
    if opened == false then
        for i = 0, 1, 0.5 do
            wait(0.5)
            part.CFrame = part.CFrame:Lerp(one, i)
            opened = true
        end
    else
        for i = 0, 1, 0.5 do
            wait(0.5)
            part.CFrame = part.CFrame:Lerp(two, i)
            opened = false
        end
    end
end)