Why does my script suddenly stop working and breaks?

This is my problem:

I have a script that make the entire game works. My game is a "Survive the Tsunamis".

What this script does is: Choose a random map, and Spawns the tsunamis then clear everything and start all that process over again.

The problem is that suddenly,after half an hour or an hour, whatever; It stops working. It spawns the map but the tsunamis dont spawn and stays like that forever. I dont know why it happens, there isnt limited rounds in the script. The only reason i think is that the script suddenly stops working and breaks.

Here is the script:

disasters = {"BigHappyHouse", "Casas Abandonadas", "Casas Apiladas", "Condominio", "Hotel de playa", "Mansion", "Base militar", "Torres Unidas", "Departamento", "Edificio de oficinas", "Avion", "Pueblo Escala", "Horror Mansion", "Hotel Defectuoso"} 

getpoints = 15 
countdownTime = 10
preparationTime = 25
LeftWaveTime = 15
RightWaveTime = 15
BigWaveTime = 25
CentralWaveTime = 30
CascadaWaveTime = 30
PreparacionTime = 10
aftermathTime = 20

countdownMessage = "La siguiente ronda será en %s segundos" 
WdisasterMessage = "El mapa será: %s" 
disasterpreparation1 = "El primer Tsunami llegará en: %s"
disasterTimeMessage1 = "Tsunami Izquierdo: %s"
disasterTimeMessage2 = "Tsunami Derecho: %s"
disasterTimeMessage3 = "GRAN Tsunami: %s"
disasterTimeMessage4 = "Olas Centrales: %s"
disasterTimeMessage5 = "Tsunami Cascada: %s"
preparacionmessage = "Preparate para el siguiente Tsunami: %s"
aftermath = "El mapa se limpiará en %s"

items = {}
leaderboard = game.Workspace:findFirstChild("BTS Leaderboard") 
local w = game.Workspace:getChildren()
for i=1,#w do
	if w[i].Name == "leaderboard" and w[i]:findFirstChild("running") ~= nil and w[i]:findFirstChild("points") ~= ni then
		leaderboard = w[i]
	end
end
for i=1,#disasters do
	local item = game.Lighting:findFirstChild(disasters[i])
	if item ~= nil then
		item.Parent = nil
		table.insert(items, item)
	else
		print("Error! ", disasters[i], " was not found!")
	end
end

function chooseDisaster()
	return items[math.random(#items)]
end

function sethint(text)
	local hint = game.Workspace:findFirstChild("hint")
	if (hint ~= nil) then
		hint.Text = text
	else
		print("Hint does not exist, creating...")
		h = Instance.new("Hint")
		h.Name = "hint"
		h.Text = text
		h.Parent = game.Workspace
	end
end

function removeHint()
	local hint = game.Workspace:findFirstChild("hint")
	if (hint ~= nil) then hint:remove() end
end

function countdown(time)
	sethint(string.format(countdownMessage, tostring(time)))
	while (time > 0) do
		wait(1)
		time = time - 1
		sethint(string.format(countdownMessage, tostring(time)))
	end
	removeHint()
	return true
end

function preparation1(time)
	sethint(string.format(disasterpreparation1, tostring(time)))
	while (time > 0) do
		wait(1)
		time = time - 1
		sethint(string.format(disasterpreparation1, tostring(time)))
	end
	removeHint()
	return true
end

function wave1(time)
	sethint(string.format(disasterTimeMessage1, tostring(time)))
	while (time > 0) do
		wait(1)
		time = time - 1
		sethint(string.format(disasterTimeMessage1, tostring(time)))
	end
	removeHint()
	return true
end

function wave2(time)
	sethint(string.format(disasterTimeMessage2, tostring(time)))
	while (time > 0) do
		wait(1)
		time = time - 1
		sethint(string.format(disasterTimeMessage2, tostring(time)))
	end
	removeHint()
	return true
end

function wave3(time)
	sethint(string.format(disasterTimeMessage3, tostring(time)))
	while (time > 0) do
		wait(1)
		time = time - 1
		sethint(string.format(disasterTimeMessage3, tostring(time)))
	end
	removeHint()
	return true
end

function wave4(time)
	sethint(string.format(disasterTimeMessage4, tostring(time)))
	while (time > 0) do
		wait(1)
		time = time - 1
		sethint(string.format(disasterTimeMessage4, tostring(time)))
	end
	removeHint()
	return true
end

function wave5(time)
	sethint(string.format(disasterTimeMessage5, tostring(time)))
	while (time > 0) do
		wait(1)
		time = time - 1
		sethint(string.format(disasterTimeMessage5, tostring(time)))
	end
	removeHint()
	return true
end

function aftermathh(time)
	sethint(string.format(aftermath, tostring(time)))
	while (time > 0) do
		wait(1)
		time = time - 1
		sethint(string.format(aftermath, tostring(time)))
	end
	removeHint()
	return true
end

function preparacion01(time)
	sethint(string.format(preparacionmessage, tostring(time)))
	while (time > 0) do
		wait(1)
		time = time - 1
		sethint(string.format(preparacionmessage, tostring(time)))
	end
	removeHint()
	return true
end

while true do
	countdown(countdownTime)

	if leaderboard ~= nil and leaderboard:findFirstChild("running") and leaderboard:findFirstChild("points") then 
		leaderboard.points.Value = getpoints
		leaderboard.running.Value = true
	end

	local m = chooseDisaster():clone()
	local LeftTsunami = game.ServerStorage.Tsunamis.TsunamiLeft:Clone()
	local RightTsunami = game.ServerStorage.Tsunamis.TsunamiRight:Clone()
	local BigTsunami = game.ServerStorage.Tsunamis.TsunamiCentral:Clone()
	local CentralTsunami = game.ServerStorage.Tsunamis.TsunamiGeneral:Clone()
	local CascadaTsunami = game.ServerStorage.Tsunamis.TsunamiCascada:Clone()
	local posicion = Vector3.new(12.5, 48.5, 29.5) 
	local jugadores = game.Players:GetChildren()

	if WdisasterMessage ~= nil then
		local msg = Instance.new("Message")
		msg.Name = "WDisasterMsg"
		msg.Text = string.format(WdisasterMessage, m.Name)
		msg.Parent = game.Workspace
		wait(3)
		msg.Parent = nil
	end

	m.Parent = game.Workspace
	m:makeJoints()
	for i = 1, #jugadores do 
		jugadores[i].Character:MoveTo(posicion) 
	end
	preparation1(preparationTime)
	LeftTsunami.Parent = game.Workspace
	wave1(LeftWaveTime)
	LeftTsunami:remove()
	preparacion01(PreparacionTime)
	RightTsunami.Parent = game.Workspace
	wave2(RightWaveTime)
	RightTsunami:remove()
	preparacion01(PreparacionTime)
	BigTsunami.Parent = game.Workspace
	wave3(BigWaveTime)
	BigTsunami:remove()
	preparacion01(PreparacionTime)
	CentralTsunami.Parent = game.Workspace
	wave4(CentralWaveTime)
	CentralTsunami:remove()
	preparacion01(PreparacionTime)
	CascadaTsunami.Parent = game.Workspace
	wave5(CascadaWaveTime)
	CascadaTsunami:remove()
	aftermathh(aftermathTime)
	m:remove()

	if leaderboard ~= nil then
		leaderboard.running.Value = false
	end
end