Network receiving problem

[WillemM]

Help, I got a very difficult problem.... I don't see the error anymore in this code. It connects fine, it sends fine. But when it comes to receiving it's useless :P

public event OnTextReceived TextReceived;
public event OnConnected Connected;
public delegate void OnTextReceived(string text);
public delegate void OnConnected();

public void Connect()
{
    try
    {
        client = new TcpClient(server,port);
        client.GetStream().BeginRead(marData,0,1024,new AsyncCallback(ResponseCallBack),null);
        
        pingSender = new Thread(new ThreadStart(PingRun));
        pingSender.Start();

        Connected();
    }
    catch(Exception ex)
    {
        throw new Exception("Can't connect (" + ex.Message + " " + ex.Source + ")");
    }
}

private void ResponseCallBack(IAsyncResult ar)
{
    int count;

    try
    {
        count = client.GetStream().EndRead(ar);
        
        if(count < 1)
        {
            pingSender.Abort();
            Disconnected();

            throw new Exception("Connection lost");
        }
                
        BuildString(marData,0,count);

        client.GetStream().BeginRead(marData,0,1024,new AsyncCallback(ResponseCallBack),null);
    }
    catch(Exception ex)
    {
        throw ex;
    }
}

public void BuildString(byte[] data, int offset, int count)
{
    int index;

    for(index = offset; index < offset + count; index++)
    {
        if(data[index] != 10 && data[index] != 13)
        {
            builder.Append(data[index]);
        }
        else
        {
            TextReceived(builder.ToString());
            builder = new StringBuilder();
        }
    }
} 

Paresh or anyone else, can you see the problem ?