Can not update membership user

 I am using the following code to update my user details
1 MembershipUser _memUser = Membership.GetUser(_createdUserProfile.UserName);
2 _memUser.Email = txtEmail.Text;
3 _memUser.IsApproved = ckbActive.Checked;
4 _memUser.ChangePassword(_memUser.GetPassword(), txtPassword.Text);
5
6 Membership.UpdateUser(_memUser);
 Change password works fine, however the email and isapproved do not change.Any ideas?
...