How to use membership

Hi All, I m new to asp.net,

 I downloded a membership website from net , it is using the System.Web.Security.SqlMembershipProvider provider its having login,create user,user only pages running successfully

 I added Password recovery page to it My page is like this---

Identity Confirmation

Answer the following question to receive your password.

 User Name: user2

 Question: user2

 Answer: *

I enter the correct answer to the question but it always gives me

 "Your answer could not be verified. Please try again."

Also I tried to Lock,UnLock,Delete the user , with this code

protected void btnDelete_Click(object sender, System.EventArgs e)

 {

Membership.DeleteUser(txtUser.Text, true);

 }

protected void btnLock_Click(object sender, System.EventArgs e)

{

 MembershipUser muser = Membership.GetUser ...