未处理 System.Runtime.Remoting.RemotingException?

未处理 System.Runtime.Remoting.RemotingException
  Message="无法加载类型“zhl.Person, Person, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null”。"
下面是Person类：
namespace zhl
{
    public class Person:MarshalByRefObject
    {
        private string m_name;        public string Name
        {
            get
            {
                return this.m_name;
            }
            set
            {
                this.m_name = value;
            }
        }
        public string SayHello()
        {
            Console.WriteLine("Hello,my name is {0}",m_name);
            return "Hi," + m_name;
        }
    }
}
然后是客户端调用：
<?xml version='1.0' encoding='utf-8'?>
<configuration>
  <system.runtime.remoting>
    <application>
      <client url='http://localhost:8000'>
        <activated type='zhl.Person,Person' />
      </client>
      <channels>
        <channel port='0' ref='Http' />
      </channels>
    </application>
  </system.runtime.remoting>
</configuration>using System;
using System.Runtime.Remoting;namespace zhl
{
    class ActiveClient
    {
        static void Main(string[] args)
        {
            RemotingConfiguration.Configure(AppDomain.CurrentDomain.SetupInformation.ConfigurationFile);            Person p = new Person();
            p.Name = "zhao hongliang";
            p.SayHello();
            Console.WriteLine("Press enter to exit.");
            Console.ReadLine();
        }
    }
}服务器端调用：
<?xml version='1.0' encoding='utf-8'?>
<configuration>
  <system.runtime.remoting>
    <application>
      <service>
        <activated type ='zhl.Person,Person' />
      </service>
      <channels>
        <channel port='8000' ref='Http' />
      </channels>
    </application>
  </system.runtime.remoting>
</configuration>using System;
using System.Runtime.Remoting;namespace zhl
{
    class ActiveServer
    {
        static void Main(string[] args)
        {
            RemotingConfiguration.Configure(AppDomain.CurrentDomain.SetupInformation.ConfigurationFile);
            Console.WriteLine("Press enter to exit");
            Console.ReadLine();
        }
    }
}
快疯掉了  找不到错误~！