при отсылании почты ошыбка
//********************************* 
MailMessage msg = new MailMessage();

             msg.To.Add("[email protected]");
             msg.From = new MailAddress("[email protected]", "Я", System.Text.Encoding.UTF8);
             msg.Subject = "PreveD";
             msg.Body = ":)...............messages...............smile";

             SmtpClient smtp = new SmtpClient();            
             smtp.Credentials = new System.Net.NetworkCredential("from", "pass");

             smtp.Port = 25;
             smtp.Host = "smtp.rambler.ru";

             smtp.Send(msg);
//***************************************************

 The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.1 Authentication required

глянь 
http://www.developerfusion.co.uk/forums/p/49849/158495/
http://forums.asp.net/p/1114258/1722656.aspx#1722656

тут вроде поясняется суть траблы. Сейчас увы проверить не могу