Static Resource Error-Collection of common programming errors

I am trying to work through a Silverlight example posted here:
http://www.silverlight.net/learn/quickstarts/choosing-which-control-to-use/

But, I am getting the following runtime error:
“Cannot find a Resource with the Name/Key WriterTemplate [Line: 14 Position: 42]”

Here is my code so far:

xaml

xaml.cs

using System;
using System.Collections.ObjectModel;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace TreeView
{
    public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent(); 

            ObservableCollection writers = new ObservableCollection() { new Writer("Chris Sells", new ObservableCollection() {"ComboBox", "ComboBoxItem"}, "Writer II"), new Writer("Luka Albrous", new ObservableCollection() {"ListBox","ListBoxItem"}, "Senior Writer"), new Writer("George Louverdis", new ObservableCollection() {"DataGrid","Binding"}, "Writer I")};

            listBox1.DataContext = writers;
            dataGrid1.DataContext = writers;
            treeView1.DataContext = writers;

        }
        public class Writer
        {
            public Writer() { }
            public Writer(string writerName, ObservableCollection listOfTypes, string writerTitle)
            {
                Name = writerName;
                Types = listOfTypes;
                Title = writerTitle;
            }

            public string Name { get; set; }
            public ObservableCollection Types { get; set; }
            public string Title { get; set; }
        }

    }
}