could not send an email message

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net.Mail;
using System.Net.Mime;// for MediaTypeNames

using System.Net;//CredentialCache
using System.Collections;
//http://msdn.microsoft.com/en-us/library/system.net.mail.mailmessage.aspx
//http://www.codeproject.com/Articles/13236/Sending-complex-emails-in-NET-1-1
namespace Email1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
       
        private void Send_Click(object sender, EventArgs e)
		{   string Myfile = "Abdk.wma";//  <----- window media audio file
            MailAddress from = new MailAddress("ksabtank@hotmail.com", "yahoo");
            MailAddress to = new MailAddress("qazwsxkhalid@yahoo.com", "hotm");
            MailMessage message = new MailMessage(from,to);//, to);
			message.Subject = "Using the new SMTP client.";
			message.Body = @"Using this new feature, you can send an e-mail message from an application very easily.";
            message.Subject = "Issue Report";
            message.Body = "Submitted By: ";// +txtName.Text + "\n";
            message.Body += "my comment";
            SmtpClient SmtpMail = new SmtpClient();//localhost);//smtp.server.com);//server);
            //SmtpMail.UseDefaultCredentials = true;
            //SmtpMail.Credentials = CredentialCache.DefaultNetworkCredentials;
            //SmtpMail.Credentials = new System.Net.NetworkCredential(str1, str2);//
            //CredentialCache cache = new CredentialCache();

            //SmtpMail.Host = "smtp.gmail.com";
            SmtpMail.Host = "smtp.hotmail.com";
            //SmtpMail.Host = "smtp.yahoo.com";
            SmtpMail.Port = 25;
            SmtpMail.Timeout = 50000;
            SmtpMail.EnableSsl = true;

            Attachment data = new Attachment(Myfile, MediaTypeNames.Application.Octet);//this is the file "Abdk.wma" 
            // Add time stamp information for the file.
            ContentDisposition disposition = data.ContentDisposition;
            disposition.CreationDate = System.IO.File.GetCreationTime(Myfile);
            disposition.ModificationDate = System.IO.File.GetLastWriteTime(Myfile);
            disposition.ReadDate = System.IO.File.GetLastAccessTime(Myfile);
            message.Attachments.Add(data);
        try {
            SmtpMail.Send(message);
		    }  
            catch (Exception ex){
			  Console.WriteLine("Exception caught in CreateTestMessage2(): {0}", 
                    ex.ToString() );			  
                                }
            }
    }
}