Lua Firestorm Event Small Error:-

[Ns Sparkz]

am using Firestorm Event | Tfs 1.2 (https://otland.net/threads/firestorm-event-tfs-1-2.237061/)
everything working fine, as soon as you enter there is fire, and then it stops and error pops outs:

Lua script error : [Main Interface]
in a timer event called from:
<Unkown scriptfile>
data/firestorm_event.lua:40: attempt to call global 'dostartfirestorm' <a nil value>
stack traceback:
[c]: in function 'dostartfirestorm'
data/firestorm.lua:40: in function <data/firestorm.lua:20>

here is my script

-- firestorm Variables
fsJoinedCountGlobalStorage = 18900 --Player joined event count / recuento de players.
fsJoinStorage = 18901 --player join storage / storage del jugador a unirse.
fsMinPlayers = 1 --min players needed when time runout / minimo de players necesarios para comenzar el evento.
fsMaxPlayers = 2 --max players to join / maximo de players.
fsTrophy = 7369 --trophy itemid / itemid del premio(que no sea stackable).
fsEventCountGlobalStorage = 18902 --firestorm Count (no move/no moverle).
fsWaitMinutes = 2 --when event has opened, how long until it starts? / cuantos minutos tarde el evento en empezar.
fsWaitingRoomPos = Position(559, 1234, 7) --middle of waiting room / punto medio de el cuarto de espera.
fsArena = Position(551, 1256, 7) --when even start where should player be teleported in the arena? / punto donde seran transportados los players.
fsArenaFromPosition = Position(544, 1248, 7) --pos of top left corner / posicion de esquina superior izquierda.
fsArenaToPosition = Position(559, 1261, 7) --pos of bottom right corner /posicion de esquina inferior derecha.
fsMiddleEventArena = Position(551, 1256, 7) --Middle pos of the arena / punto medio de la arena
fsWaitingRoomRadiusX = 5 --depends how big the waiting room is 20sqm to x / depende de lo grande la sala de espera en x
fsWaitingRoomRadiusY = 5 --depends how big the waiting room is 20sqm to y / depende de lo grande la sala de espera en y
fsEventArenaRadiusX = 12 --Depends how big the firestorm arena is 50sqm to x / depende de lo grande de la arena en x
fsEventArenaRadiusY = 12 --Depends how big the firestorm arena is 50sqm to y / depende de lo grande de la arena en y
fsStartedGlobalStorage = 18903 -- Value: 0 == false, 1 == true, 2 == started --State of the event
fsCreateTeleportPosition = Position(626, 1099, 7) --Where should the teleport be created? / posicion donde sera creado el teleport?
function startfirestorm()
    local specs = Game.getSpectators(fsWaitingRoomPos, false, true, 0, fsWaitingRoomRadiusX, 0, fsWaitingRoomRadiusY)
    if Game.getStorageValue(fsJoinedCountGlobalStorage) <= fsMinPlayers then
        for i = 1, #specs do
            specs[i]:teleportTo(specs[i]:getTown():getTemplePosition(), false)
            specs[i]:setStorageValue(fsJoinStorage, 0)
        end
        resetfsVariables()
        Game.broadcastMessage('firestorm Event failed to start, because of to little players joined the event!', MESSAGE_STATUS_WARNING)
        return true
    end
    for i = 1, #specs do
        local rX, rY, rZ
        rX = math.random(fsArenaFromPosition.x, fsArenaToPosition.x)
        rY = math.random(fsArenaFromPosition.y, fsArenaToPosition.y)
        rZ = math.random(fsArenaFromPosition.z, fsArenaToPosition.z)
        specs[i]:teleportTo(Position(rX, rY, rZ))
    end
    Game.broadcastMessage("firestorm Event has started, good luck to all participant.", MESSAGE_STATUS_WARNING)
    Game.setStorageValue(fsStartedGlobalStorage, 2)
    dostartfirestorm()
end
function doStartfirestorm()
        if  Game.getStorageValue(fsJoinedCountGlobalStorage) > fsMaxPlayers then return false end
                if Game.getStorageValue(fsStartedGlobalStorage) == 2 then
                local specs = Game.getSpectators(fsArena, false, true, 0, 10, 0, 10)
                 for i = 1, #specs do
        local randX, randY, randZ
        randX = math.random(fsArenaFromPosition.x, fsArenaToPosition.x)
        randY = math.random(fsArenaFromPosition.y, fsArenaToPosition.y)
        randZ = math.random(fsArenaFromPosition.z, fsArenaToPosition.z)
                local randfire = Position(randX, randY, randZ)
                 local randX1, randY1, randZ1
        randX1 = math.random(fsArenaFromPosition.x, fsArenaToPosition.x)
        randY1 = math.random(fsArenaFromPosition.y, fsArenaToPosition.y)
        randZ1 = math.random(fsArenaFromPosition.z, fsArenaToPosition.z)
                local randfire1 = Position(randX1, randY1, randZ1)
            local creature, players = nil, Game.getPlayers()
                                                 for i = 1, #players do
                                                 creature = players[i]
                doSendDistanceShoot(fsArenaFromPosition, randfire, 4)
                doSendDistanceShoot(fsArenaToPosition, randfire, 4)
                doSendDistanceShoot(Position(544, 1248, 7), randfire, 4)
                doSendDistanceShoot(Position(560, 1265, 7), randfire, 4)
                doSendMagicEffect(randfire, 7)
           local target = Tile(randfire):getBottomCreature()
           local MaxHealth = target:getMaxHealth()
             if target then
                Creature(target):addHealth(-MaxHealth)
             end
                end
                                end
            addEvent(doStartfirestorm, 500)
        end
end
function resetfsVariables()
        Game.setStorageValue(fsEventCountGlobalStorage, 0)
        Game.setStorageValue(fsJoinedCountGlobalStorage, 0)
        Game.setStorageValue(fsStartedGlobalStorage, 0)
end