Why wont this work?!!!

I'm EXTREMELY frustrated because a double-jump script JUST REFUSES to work in online mode! PLEASE SOMEONE explain why this darn FREAKIN SCRIPT wont work?!!

The error i get is: "Humanoid is not a valid member of model"

WTF... HOWWWWWWWWWWWWWWWWWWWWWW

repeat wait() until script.Parent.Parent.Character and script.Parent.Parent.Character.Humanoid  ~= nil
wait()
print("loaded")
--Made by FromLegoUniverse
--Super easy script
--Put this in StarterGui or StarterPack

--The "Creative" option makes it so you can jump infinitly (True if yes, False if no)
--Note: I modified a decent amount of this. So the update function and "Creative" option do nothing.
local FirstJump = false
local MidJump = false
local Mouse = script.Parent.Parent:GetMouse()
local animation = script.db
debounce = false

function onKeyDown(key)
	Mouse.KeyDown:connect(function(Key)
	if string.byte(Key) == 101 and debounce == false then
		debounce = true
		MidJump = true
	local animPLAY = script.Parent.Parent.Character.Humanoid:LoadAnimation(animation)
	animPLAY:Play()
		script.Parent.Parent.Character.Torso.Velocity = Vector3.new(0,90,0)
		wait(3)
		debounce = false
	    end
	end)
end

function Update()
	if script.Parent.Parent.Character.Humanoid.Jump == true then
		FirstJump = true
	else
		FirstJump = false
		MidJump = false
	end
end


--Mouse.KeyDown:connect(onKeyDown)
wait()
script.Parent.Parent.Character.Humanoid.Jumping:connect(onKeyDown)
--script.Parent.Parent.Character.Humanoid.Jumping:connect(Update)

You need more information, such as, where does that script go? Did you place that in the workspace? If you placed it in the workspace, of course it won't work. Basically, you did not tell us ANYTHING about the address, which would be important.