Problem in code to send email through my application

System.Net.Mail.MailMessage msgMail = new System.Net.Mail.MailMessage("xxxx@xxxxx.com", txtEmail.Text);

       string mailid = "xxxx@bexxxx.com";
       string Pasword = xxxxx;

       string msg = null;
       string mTo = To;
       string mFrom = mailid;


       msgMail.Subject = Registration Confirmation;
       System.Text.StringBuilder SB = new System.Text.StringBuilder();
       System.IO.StringWriter Sw = new System.IO.StringWriter(SB);


       string mMsg = "hi"

       mMsg = mMsg + SB.ToString();

       try
       {
           msgMail.To.Add(mTo);
           msgMail.From = new System.Net.Mail.MailAddress(mFrom);
           msgMail.IsBodyHtml = true;
           msgMail.Body = mMsg;
           msgMail.Priority = System.Net.Mail.MailPriority.High;
           System.Net.Mail.SmtpClient smtp = new System.Net.Mail.SmtpClient();
           smtp.Host = "mymail.brinkster.com";
           smtp.Port = 25;
           smtp.Credentials = new System.Net.NetworkCredential(mFrom, Pasword);
           smtp.EnableSsl = true;

           smtp.Send(msgMail);

       }