I have added the session code to your login page, please use this version of the page to test out what values are in the session. When you first go to this page login and then go back to this page to see what is printed at the top. Once you have done this go to the logout page to logout then go back to the login page. You should see what is in the session after you logout. Please post back with all of the values that you are getting after you login and after you logout.
If there are any passwords present you can mask them.