back button after logout

Hi,

My application env is Tomcat 5.0, Struts.

Currently when user logs out and hits the back button of browser it show the page error.html page which I have mentioned in web.xml. this html page has a link to main_menu.do.

Right now when user clicks the above link it does not take him anywhere and stays there.

I want to send user back to login page if he is logged out. but i cannot give link to login.do instead of main_menu.do because this page is being used by other server errors too and it takes user back to main menu page.

Where should I add code to check if user has logged out and send him back to login page if he clicks main_menu.do link in error page?

I have tried to debug it....but it's not going to the action where I can write some code to check it...it just refreshes the same page.

Please advise.

Thanks