What does it mean when i attempt to call a _G. function with a "nil" value? (WARNING: LOTS OF CODE)

i have 3 scripts all stringed together, but for some reason, it wont let me call my _G. functions. It calls them a "nil" value. "Players.SweetAsCreampie.PlayerGui.Buttony:36: attempt to call field 'CancelTransform' (a nil value)"

here is the the three local scripts in StarterGui Buttony:

local UIS = game:GetService('UserInputService')
local pressing
local Energy = 90
local player = game.Players.LocalPlayer
local character = player.Character

if not player or not character.Parent then
    character = player.CharacterAdded:wait()
end
done = false
UIS.InputBegan:connect(function(inputObject, gameProcessedEvent)
    if not gameProcessedEvent then
        if inputObject.KeyCode == Enum.KeyCode.C then

            pressing = true
            while pressing do
                if done == false then
                _G.FIRE()               
                _G.Squat()
                wait(2)
                done = true
                _G.TransformReady()
                else
                _G.PowerSquat()

                wait(5.2)
                Energy = Energy + 1
                end
                    end
                    end
                    _G.GetEnergy(Energy)
            print('Charging....')
    end
    _G.NOFIRE()
    done = false
    _G.CancelTransform()
    end)
    _G.NOFIRE()
    done = false
    _G.CancelTransform()

UIS.InputEnded:connect(function(inputObject, gameProcessedEvent)
    if not gameProcessedEvent then
        if inputObject.KeyCode == Enum.KeyCode.C then
            pressing = false
            print('u stopped pressing :)')
            _G.NOFIRE()
        end
    end
end)

Flame:

local player = game.Players.LocalPlayer
local character = player.Character
local enraged = false
if not character or not character.Parent then
    character = player.CharacterAdded:wait()
end
local torso = character.LowerTorso
local fire = Instance.new("Fire")
fire.Parent = torso
fire.Enabled = false
fire.Heat = 6
fire.Size = 6

local FireOn = false

_G.FIRE = function()
    fire.Enabled = true
    if enraged == false then
    fire.Color = Color3.new(255,255,255)
    fire.SecondaryColor = Color3.new(255,255,255)
    end 
end
_G.Transform = function()
    enraged =true
end
_G.NOFIRE = function()
    if enraged == true then

    else
    fire.Enabled = false
    end
end

and finally, Enragements:

local player = game.Players.LocalPlayer
local character = player.Character
local Ready = false
_G.TransformReady = function()
    Ready = true
end
_G.CancelTransform = function()
    Ready = false
end

if not character or not character.Parent then
    character = player.CharacterAdded:wait()
end
local torso = character.LowerTorso
local fire = Instance.new("Fire")
fire.Parent = torso
fire.Enabled = false
fire.Heat = 16
fire.Size = 10
fire.Enabled = false
UIS.InputBegan:connect(function(inputObject, gameProcessedEvent)
    if not gameProcessedEvent then
        if inputObject.KeyCode == Enum.KeyCode.G then
            if Ready == true then
                fire.Enabled = true
                fire.Color = Color3.new(240,0,0)
                fire.SecondaryColor = Color3.new(255,0,0)
            end         
            end
        end

`