Loading an object from a db4o database.

Question

I am developing an e-commerce website that utilises db4o as the backend. All was well until last week when I came across a problem that I have been unable to solve. The code below is quite straight forward. I open a database file, save an object and then try to retrieve it. However I get nothing back. The "users" variable has a count of zero.

public class Program
{
    private static string _connectionString = string.Format(@"c:\aaarrrr.db4o");

    static void Main(string[] args)
    {
        TestUser container = new TestUser() { id = 1, Name = "Mohammad", Surname = "Rafiq" };

        Db4oFactory.Configure().Diagnostic().AddListener(new DiagnosticToConsole());

        using (var dbc = Db4oFactory.OpenFile(_connectionString))
        {
            dbc.Store(container);
        }

        IList<TestUser> users = null;

        using (var dbc = Db4oFactory.OpenFile(_connectionString))
        {
            users = dbc.Query<TestUser>(x => x.id == 1).ToList();
        }

        if (users.Count > 0)
        {
            Console.WriteLine("{0} {1} with id of {2}", users.First().Name, users.First().Surname, users.First().id);
        }
        else
        {
            Console.WriteLine("\nNo data returned.");
        }

        Console.ReadLine();
    }
}

public class TestUser
{
    [Indexed]
    private int _id = 0;
    private string _name = string.Empty;
    private string _surname = string.Empty;

    public int id { get { return _id; } set { _id = value; } }
    public string Name { get { return _name; } set { _name = value; } }
    public string Surname { get { return _surname; } set { _surname = value; } }
}

I have attached db4o diagnostic listener and I see nothing in the console output. Everything seems fine. I know I am writing to the file because I can see the file size increase and the timestamp is also updated. I have checked all the project settings and they are all set to default. I am using .net 4, visual studio 2010 beta and windows 7. I have done some reading regarding reflection permission but I cant see how this applies here. Any help or ideas would be knidly appreciated.