Client and Server Program

[C# Programming]

A hi to all programming gurus
i am an amature in network programming i have written an simple program for making a client and server in c#
the cleint sends a msg and the server displays it in the listbox(lbconnections)
The Problem is that----
this application runs perfectly after being deployed and afterward when i again use it it crashes (port already bieng used error)
plz help me with this plzzzzzzzzzzzzzzzzzzzzzzzz..............http://www.barakasoft.com/script/Forums/Images/smiley_confused.gifhttp://www.barakasoft.com/script/Forums/Images/smiley_confused.gifhttp://www.barakasoft.com/script/Forums/Images/smiley_confused.gif

********************************coding for server*******************************************
using System;
using System.Threading;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net.Sockets;
using System.Net;

namespace server
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
public void recieve()
{
try
{
UdpClient server = new UdpClient(8080);
while (true)
{
IPEndPoint ip = new IPEndPoint(IPAddress.Any, 0);
byte[] recieved = server.Receive(ref ip);
string returndata = Encoding.ASCII.GetString(recieved);
listBox1.Items.Add(ip.Address.ToString() + " : " + returndata.ToString());
}
}
catch (SocketException ex)
{
MessageBox.Show(ex.Message);
}
}

private void Form1_Load(object sender, EventArgs e)
{
Thread server = new Thread(new ThreadStart(recieve));
server.Start();
}
}
}

***************************************CODING FOR CLIENT*********************************************
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net.Sockets;
using System.Net;

namespace ser_cli
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
UdpClient client = new UdpClient();
client.Connect(tbHost.Text, 8080);
byte[] send = Encoding.ASCII.GetBytes("HELLO WORLD?");
client.Send(send, send.Length);
}
}
}