Passcode GUI won't work?

Hi, I wanted to make a Passcode GUI for my Place. Everything works but when I enter the password and press the enter key, It wont tell that the password is right or and It wont close the GUI if the password is correct. Heres the script so you can see what mistakes i have done. The script is placed in the StarterPack and the script is a LocalScript.

code = "EnterCodeHere"
---------------------------------!WARNING!---------------------------------------------
                          ---DON'T CHANGE ANYTHING!---
Player = script.Parent.Parent
Mouse = Player:GetMouse()
codegui = script.Parent.Parent.StarterGui.CodeGUI
codeteller = script.Parent.Parent.StarterGui.CodeGUI.Background.PasscodeTeller
codetype = script.Parent.Parent.StarterGui.CodeGUI.Passcode.TypeCodeHere

function onKeyDown()
local key = key.lower()
    if key:byte() == 13 then -- From this part it stops working...
        if (codetype == code) then 
            codeteller.Text = "Correct"
            wait(2)
            script.Parent.Parent.Character.Humanoid.WalkSpeed = 16
            codegui:remove()
        else
            codeteller.Text = "Wrong"
            wait(3)
            codeteller.Text = "Passcode"
        end
    end
end
Mouse.KeyDown:connect(onKeyDown) 

Thanks! -Chillu4