[Zope] Redirection and Request Variables

Hi, I've got a page template that display a file using the id given in the request. I also got login/logout functionality on the site using exUserFolder, now I want that If the user looks at the file display he can click the login and after that gets back to the file display page. But this doesn't work, After clicking on the login Button I get a KeyError about the variable which holds the id - after a reload everything is fine. The variable is encoded within the URL using the QUERY_STRING. Is it somehow possible to get rid of this error? If you need more information feel free to ask. Andreas -- Beware of low-flying butterflies.