hey guys, i have made and administrator area which when logged in displays the administrator area in frames.

Portion of login area which contains frames...
PHP Code:
if (isset($_SESSION['administrator']))
//administration area frame 

<frameset rows="*" cols="180,*" frameborder="YES" border="0" framespacing="0">
  <frame src="frame4.php" name="leftFrame" scrolling="YES">
  <frameset rows="20,*" frameborder="NO" border="0" framespacing="0">
    <frame src="frame3.php" name="topFrame" scrolling="NO" noresize>
    <frame src="frame2.php" name="middleFrame">

The left payne contains the logout link which opens logout.php in _top Target.

PHP Code:

When i logout and i press the back button it displays this message

Warning: Page has Expired The page you requested was created using information you submitted in a form. This page is no longer available. As a security precaution, Internet Explorer does not automatically resubmit your information for you.

To resubmit your information and view this Web page, click the Refresh button.

But apon pressing the refresh button it displays the administrator area

Is there anything i need to consider when logging out with frames or have i done something wrong?