unhandled exception in game.chat.chatmodules.chatbot?

alright. so i have a teensy-weensy problem with the chat. i was trying to make a bot for my game. as seen in the roblox blog, (https://blog.roblox.com/2017/01/new-chat-system-api/) i followed the roblox wiki instructions, (http://wiki.roblox.com/index.php?title=Lua_Chat_System) i made my chatbot. But there are a few errors when copying the scripts to the chat. here's where the error originated.

--  // FileName: MessageLabelCreator.lua
local OBJECT_POOL_SIZE = 50

local module = {}
--////////////////////////////// Include
--//////////////////////////////////////
local Chat = game:GetService("Chat")
local clientChatModules = Chat:WaitForChild("ClientChatModules")
local messageCreatorModules = clientChatModules:WaitForChild("MessageCreatorModules")
local messageCreatorUtil = require(messageCreatorModules:WaitForChild("Util"))
local modulesFolder = script.Parent
local ChatSettings = require(clientChatModules:WaitForChild("ChatSettings"))
local moduleObjectPool = require(modulesFolder:WaitForChild("ObjectPool"))
local MessageSender = require(modulesFolder:WaitForChild("MessageSender"))

--////////////////////////////// Methods
--//////////////////////////////////////
local methods = {}
methods.__index = methods

function ReturnToObjectPoolRecursive(instance, objectPool)
    local children = instance:GetChildren()
    for i = 1, #children do
        ReturnToObjectPoolRecursive(children[i], objectPool)
    end
    instance.Parent = nil
    objectPool:ReturnInstance(instance)
end

function GetMessageCreators()
    local typeToFunction = {}
    local creators = messageCreatorModules:GetChildren()
    for i = 1, #creators do
        if creators[i]:IsA("ModuleScript") then
            if creators[i].Name ~= "Util" then
                local creator = require(creators[i])
                typeToFunction[creator[messageCreatorUtil.KEY_MESSAGE_TYPE]] = creator[messageCreatorUtil.KEY_CREATOR_FUNCTION]
            end
        end
    end
    return typeToFunction
end

function methods:WrapIntoMessageObject(messageData, createdMessageObject)
    local BaseFrame = createdMessageObject[messageCreatorUtil.KEY_BASE_FRAME]
    local BaseMessage = nil
    if messageCreatorUtil.KEY_BASE_MESSAGE then
        BaseMessage = createdMessageObject[messageCreatorUtil.KEY_BASE_MESSAGE]
    end
    local UpdateTextFunction = createdMessageObject[messageCreatorUtil.KEY_UPDATE_TEXT_FUNC]
    local GetHeightFunction = createdMessageObject[messageCreatorUtil.KEY_GET_HEIGHT]
    local FadeInFunction = createdMessageObject[messageCreatorUtil.KEY_FADE_IN]
    local FadeOutFunction = createdMessageObject[messageCreatorUtil.KEY_FADE_OUT]
    local UpdateAnimFunction = createdMessageObject[messageCreatorUtil.KEY_UPDATE_ANIMATION]

    local obj = {}

    obj.ID = messageData.ID
    obj.BaseFrame = BaseFrame
    obj.BaseMessage = BaseMessage
    obj.UpdateTextFunction = UpdateTextFunction or function() warn("NO MESSAGE RESIZE FUNCTION") end
    obj.GetHeightFunction = GetHeightFunction
    obj.FadeInFunction = FadeInFunction
    obj.FadeOutFunction = FadeOutFunction
    obj.UpdateAnimFunction = UpdateAnimFunction
    obj.ObjectPool = self.ObjectPool
    obj.Destroyed = false

    function obj:Destroy()
        ReturnToObjectPoolRecursive(self.BaseFrame, self.ObjectPool)
        self.Destroyed = true
    end

    return obj
end

function methods:CreateMessageLabel(messageData, currentChannelName)
    local messageType = messageData.MessageType
    if self.MessageCreators[messageType] then
        local createdMessageObject = self.MessageCreators[messageType](messageData, currentChannelName)
        if createdMessageObject then
            return self:WrapIntoMessageObject(messageData, createdMessageObject)
        end
    elseif self.DefaultCreatorType then
        local createdMessageObject = self.MessageCreators[self.DefaultCreatorType](messageData, currentChannelName)
        if createdMessageObject then
            return self:WrapIntoMessageObject(messageData, createdMessageObject)
        end
    else
        error("No message creator available for message type: " ..messageType)
    end
end

--///////////////////////// Constructors
--//////////////////////////////////////

function module.new()
    local obj = setmetatable({}, methods)

    obj.ObjectPool = moduleObjectPool.new(OBJECT_POOL_SIZE)
    obj.MessageCreators = GetMessageCreators() -- error is here.
    obj.DefaultCreatorType = messageCreatorUtil.DEFAULT_MESSAGE_CREATOR

    messageCreatorUtil:RegisterObjectPool(obj.ObjectPool)

    return obj
end

function module:GetStringTextBounds(text, font, textSize, sizeBounds)
    return messageCreatorUtil:GetStringTextBounds(text, font, textSize, sizeBounds)
end

return module

any help?