[This is preliminary documentation and subject to change]
The Session_OnEnd event occurs when a session is abandoned or times out. Of the server built-in objects, only the Application Object, Server Object, and Session Object objects are available.
<SCRIPT LANGUAGE=ScriptLanguage
RUNAT=Server>
Sub Session_OnEnd
. . .
End Sub
</SCRIPT>
You cannot call the MapPath method in the Session_OnEnd script.
Session_OnStart, Application_OnEnd