Socket Crash!!!

Here is my code. When I launch the program, there is a crash!
/***********************************************************/

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.Text;

public class NetWorkClient : MonoBehaviour, IDisposable{

public GameObject prefab;

private int port;
private string hostIp;
private bool socketInUse = true;
private Connection signalConnection = null;
private Connection dataConnection = null;
private Socket signalSocket = null;
private Socket dataSocket = null;
private IPEndPoint endPoint = null;

private enum State {Normal, Suspended, Stopped};

public void Start() {
string hostName = Dns.GetHostName();
string hostIp = Dns.GetHostByName(hostName).AddressList[0].ToString();
System.Console.Write(hostIp + "\n");
Debug.Log("Host IP: " + hostIp);

this.hostIp = hostIp;
this.port = 20000;

endPoint = new IPEndPoint(IPAddress.Parse(this.hostIp), this.port);
signalSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
signalSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
signalSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.DontLinger, true);

dataSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
dataSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
dataSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.DontLinger, true);

CreateSignalThread();
CreateDataThread();
}

protected virtual void Dispose(bool disposing) {
if (disposing) {
this.signalConnection.Abort();
this.dataConnection.Abort();
}
}

public void Dispose() {
Dispose(true);
GC.SuppressFinalize(this);
GC.Collect();
}

public void OnApplicationQuit() {
Dispose();
Debug.Log("Game Over");
}

public void CreateSignalThread() {
Thread signalThread = new Thread(new ThreadStart(SignalCommunicate));
signalConnection = new Connection(signalSocket, signalThread);
signalThread.Start();
}

public void SignalCommunicate() {
Debug.Log("Waiting for SignalConnection...");
signalSocket.Connect(endPoint);
Debug.Log("SignalConnection Established");

}

public void CreateDataThread() {
Thread dataThread = new Thread(new ThreadStart(DataCommunicate));
dataConnection = new Connection(dataSocket, dataThread);
dataThread.Start();
}

public void DataCommunicate() {
Debug.Log("Waiting for DataConnection...");
dataSocket.Connect(endPoint);
Debug.Log("DataConnection Established");
}

private class Connection {
private Socket mySocket;
private Thread myThread;

public Connection(Socket socket) {
this.mySocket = socket;
myThread = null;
}

public Connection(Socket socket, Thread thread) {
this.mySocket = socket;
this.myThread = thread;
}

public Thread MyThread {
get { return myThread; }
set { myThread = value; }
}

public Socket MySocket {
get { return mySocket; }
set { mySocket = value; }
}

public void Abort() {
if(mySocket.Connected) {
try {
mySocket.Shutdown(SocketShutdown.Both);
} catch(SocketException se) {
Debug.Log(se.ToString());
}
}
mySocket.Close();
Debug.Log("Client socket shut down");
myThread.Abort();
}
}

/*
public void Interact() {
while (true) {
string recvStr = "";
byte[] recvBytes = new byte[1024];
int bytes = mySocket.Receive(recvBytes, recvBytes.Length, 0);

if (bytes == 0)
break;

recvStr += Encoding.ASCII.GetString(recvBytes, 0, bytes);

Debug.Log("server gets message: " + recvStr);
string sendStr = "OK! Client send message successful!";
byte[] bs = Encoding.ASCII.GetBytes(sendStr);
mySocket.Send(bs, bs.Length, 0);

Thread.Sleep(100);
}
Abort();
} */

}