Session end while getting an exception

I have a problem. I have designed a shopping app where I use the session state to store some information. I ahve noticed that every time my code generates an exception, the session_end event fires. Why is it like that, and what can I do to avoid it??? This is really annoying since all I want to do is to display a javascript messagebox and allow the user to continue shopping. As it works now, i must redirect the user to the login page every time an exception is caught.


/Henrik