[Zope] Can't get dtml-in to work!

Hi, this must be a very dumb question, but I can't find the mistake. Anyone seeing why the the following DTML does not work? It does not print anything besides 'Hello', though I created several folders in the one where the document below resides. Choosing different meta types doesn't help either... <dtml-var standard_html_header> <h2><dtml-var title_or_id></h2> <p> Hello <dtml-in expr="objectValues('Folder')"> Out there ! <dtml-var sequence-length> <dtml-var getId> </dtml-in> </p> <dtml-var standard_html_footer> Anyone knows help? Regards, Lars