Email Verfication in Simple User Registration Form using ASP.Net and SQL is not working

Hi Team,
I am trying to create a simple user registration form in which Email Verification is not working.
I am getting SMTP Exception. Please see images on below link:-
http://social.microsoft.com/Forums/en-US/7bcf7011-538d-4c56-8a59-65ee3434a062/email-verfication-in-simple-user-registration-form-using-aspnet-and-sql-is-not-working?forum=mas