SmtpMail发送错误，Could not access 'CDO Message' object

xp 系统， vs 2003MailMessage testMail = new MailMessage();
testMail.From = "[email protected]";
testMail.To = "[email protected]";
testMail.Subject = "Test remote";
testMail.BodyFormat = MailFormat.Html;
testMail.Body = "Test Mail";
testMail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", "1"); testMail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername", "username"); testMail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword", "userpassword"); 
                  ///SmtpMail.SmtpServer.Insert(0,"202.108.45.161");
SmtpMail.SmtpServer.Insert(0,"smtp.126.com") ;
SmtpMail.Send(testMail);
关了防火墙，还是出现同样的问题
哪位大大给解决一下吧。