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