Nick Gravelyn's Tile Engine Editor Error

Hi,

I am following the Nick Gravelyn online Tile Engine tutorial and have gotten as far as the TileEditor. When I try to run the game, I am met with an error which reads:

"Field 'TileEditor.Form1.spriteBatch' is never assigned to, and will always have its default value null c:\users\user\documents\visual studio 2010\Projects\TileGame\TileEditor\Form1.cs"

The only thing that is displayed is a white screen with a red X. The code is below.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Windows.Forms;
using System.IO;
using System.Linq;

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.GamerServices;

using TileEngine;




namespace TileEditor
{
    public partial class Form1 : Form
    {
        SpriteBatch spriteBatch;

        Camera camera = new Camera();

        TileLayer tileLayer = new TileLayer(new int[,]
        {
            { 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3,},
            { 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3,},
            { 1, 1, 0, 0, 0, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 2, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3,},
            { 1, 1, 0, 0, 0, 1, 1, 2, 2, 2, 2, 2, 3, 1, 1, 1, 1, 1, 1, 1, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3,},
            { 1, 1, 0, 0, 0, 1, 1, 2, 2, 2, 2, 2, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3,},
            { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3,},
            { 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3,},
            { 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3,},
            { 1, 1, 0, 0, 0, 1, 1, 2, 2, 2, 2, 2, 3, 1, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 2, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3,},
            { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3,},
            { 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3,}
        });

        public GraphicsDevice GraphicsDevice
        {
            get { return tileDisplay1.GraphicsDevice; }
        }

        public Form1()
        {
            InitializeComponent();
            tileDisplay1.OnInitialize += new EventHandler(tileDisplay1_OnInitialize);
            tileDisplay1.OnDraw += new EventHandler(tileDisplay1_OnDraw);
        }

        public Texture2D Texture2DFromFile(string fileName)
        {
             Texture2D texture;
             FileStream stream = new FileStream(fileName, FileMode.Open);
             texture = Texture2D.FromStream(GraphicsDevice, stream);

             stream.Close();
             return texture;
        }

        void tileDisplay1_OnInitialize(object sender, EventArgs e)
        {
            spriteBatch = new SpriteBatch(GraphicsDevice);

            tileLayer.AddTexture(Texture2DFromFile("Tiles/se_free_dirt_texture"));
            tileLayer.AddTexture(Texture2DFromFile("Tiles/se_free_grass_texture"));
            tileLayer.AddTexture(Texture2DFromFile("Tiles/se_free_ground_texture"));
            tileLayer.AddTexture(Texture2DFromFile("Tiles/se_free_mud_texture"));
            tileLayer.AddTexture(Texture2DFromFile("Tiles/se_free_road_texture"));

        }
        
        
        
        void tileDisplay1_OnDraw(object sender, EventArgs e)
        {
            tileLayer.Draw(spriteBatch, camera);
        }
    }
}

I cannot figure out what exactly I am doing wrong here, so any advice would be helpful. Thanks.