关于Nhibernate配置问题

我是刚开始用Nhibernate，老是出现问题：
映射文件user.hbm.xml找不到架构信息，是和我的Nhibernate的版本有关吗？
有没有朋友曾遇到过类似的问题，帮小弟一把，多谢了！
具体代码如下：
1.Users类
namespace guestbook.data
{
    public class Users
    {
        public Users()
        { }

        private System.Int32 _flag;
        public System.Int32 flag
        {
             get { return _flag; }
            set { _flag = value; }
        }

        private System.String _email;
        public System.String email
        {
             get { return _email; }
            set { _email = value; }
        }

        private System.Int32 _id;
        public System.Int32 id
        {
             get { return _id; }
            set { _id = value; }
        }

        private System.DateTime _regtime;
        public System.DateTime regtime
        {
             get { return _regtime; }
            set { _regtime = value; }
        }

        private System.String _Name;
        public System.String Name
        {
             get { return _Name; }
            set { _Name = value; }
        }

        private System.String _password;
        public System.String password
        {
             get { return _password; }
            set { _password = value; }
        }
    }

}
2.User.hbm.xml文件
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-1.0">
  <class name="guestbook.data.users, guestbook.data" table="G_users">
    <id name="id" column="id" type="Int32">
      <generator class="identity" />
    </id>
    <property name="Name" type="String(20)" column="Name" />
    <property name="email" type="String(40)" column="email" />
    <property name="password" type="String(20)" column="password" />
    <property name="flag" type="Int32" column="flag" />
    <property name="regtime" type="DateTime" column="regtime" />
  </class>
</hibernate-mapping>
3.App.Config
<?xml version="1.0" encoding="utf-8" ?>

<configuration>

  <configSections>

    <section name="nhibernate" type="System.Configuration.NameValueSectionHandler, System, Version=1.0.3300.0,Culture=neutral, PublicKeyToken=b77a5c561934e089" />

  </configSections>

  <nhibernate>

    <add key="hibernate.connection.provider" value="NHibernate.Connection.DriverConnectionProvider" />

    <add key="hibernate.dialect" value="NHibernate.Dialect.MsSql2000Dialect" />

    <add key="hibernate.connection.driver_class" value="NHibernate.Driver.SqlClientDriver" />

    <add key="hibernate.connection.connection_string" value="Server=localhost;initial catalog=NhibernateTest;User ID=sa;Password=sa;Min Pool Size=2" />

  </nhibernate>

</configuration>

4.测试代码
namespace guestbook.test
{
    /**/
    /// <summary>
    /// DataLayerUsersTest 的摘要说明。
    /// </summary>
    [TestFixture]
    public class DataLayerUsersTest
    {
        public DataLayerUsersTest()
        {

        }

        [Test]
        public void testAdd()
        {
            Configuration cfg = new Configuration();
            cfg.AddXmlFile("User.hbm.xml");

            ISessionFactory f = cfg.BuildSessionFactory();
            ISession s = f.OpenSession();
            ITransaction t = s.BeginTransaction();

            Users newUser = new Users();
            newUser.Name = "易做图snake";
            newUser.password = "24976904";
            newUser.email = "易做图snakes@gmail.com";
            newUser.regtime = DateTime.Now;

            s.Save(newUser);

            t.Commit();
            s.Close();

        }
    }
} --------------------编程问答-------------------- 注意大小写和命名空间, 配置文件和实体最好用mygeneration 生成,不要手写,很容易出错的 --------------------编程问答-------------------- 看了
很是麻烦 --------------------编程问答-------------------- 不要手写,很容易出错 --------------------编程问答-------------------- 不是版本的问题，是设置的问题！

补充：.NET技术 ,  .NET技术前瞻