Java RMI连接拒绝承载异常

我正在用java和rmi开发一个简单的基于服务器的计算程序。但是，服务器未初始化，出现以下异常

Initializing Server
Remote Server Error:Connection refused to host: 192.168.1.3; nested exception is:
    java.net.ConnectException: Connection refused: connect

我已关闭我的microsoft防火墙。此后，问题依然存在。以下是我正在运行的代码：

  import java.rmi.*;
    import java.rmi.Naming.*;
    import java.rmi.server.*;
    import java.rmi.registry.*;
    import java.net.*;
    import java.util.*;

    interface mathInterface extends Remote
    {
     public int add(int a,int b) throws RemoteException;
     public int subt(int a,int b) throws RemoteException;
     public int mult(int a,int b) throws RemoteException;
     public int div(int a,int b) throws RemoteException;
    }

    public class mathServer extends UnicastRemoteObject implements mathInterface
    {
                public mathServer() throws RemoteException
                {
                                System.out.println("Initializing Server");
    }
    public int add(int a,int b)
    {
                                return(a+b);
                }
                public int subt(int a,int b)
                    {
                                                return(a-b);
                }
                public int mult(int a,int b)
                    {
                                                return(a*b);
                }
                public int div(int a,int b)
                    {
                                                return(a/b);
                }
                public static void main(String args[])
                {
                                try
                                {
                                mathServer ms=new mathServer();
                                java.rmi.Naming.rebind("MathServ",ms);
                                System.out.println("Server Ready");
                    }
                    catch(RemoteException RE)
                    {
                                                System.out.println("Remote Server Error:"+ RE.getMessage());
                                                System.exit(0);
                                }
                                catch(MalformedURLException ME)
                                {
                                                System.out.println("Invalid URL!!");
                                }
                }
}

---

请帮我解决这个问题。

您还没有启动RMI注册表