Hi, I've just started programming in Processing and  I'm trying to write a simple server for an online game. The server needs to get 4 integers from one player and send them to the other player. I get the following error:

java.net.SocketException: socket closed
at java.net.PlainSocketImpl.socketAccept(Native Method)

Here is the source code:

import processing.net.*;

boolean myServerRunning = true;
Server myServer;
int xFirst,yFirst,xLast,yLast;

void setup()
{
 myServer = new Server(this, 10001);
}

if((keyPressed)&&(key == 'S')) {
   myServer.stop();
   myServerRunning = false;  
}

void draw()
{
 if (myServerRunning == true)
 {
   Client firstClient = myServer.available();
   if (thisClient != null) {
     if (thisClient.available() > 0) {
       xFirst = thisClient.read();
       yFirst = thisClient.read();
       xLast  = thisClient.read();
       yLast  = thisClient.read();
       Client secondClient = myServer.available();
       secondClient.write(xFirst);
       secondClient.write(yFirst);
       secondClient.write(xLast);
       secondClient.write(yLast);
     }
   }
 }
}

I've closed my firewall and tried different port numbers. Can you help me with this problem?