[Zope] Rescheduling of Xron Methods

Hi folks, I have installed Xron to do some recurring tasks automatically. However the Xron DTML Methods is not rescheduled, but only executed once. The source code of the DTML Method is: Content-type: text/plain <dtml-call "Control_Panel.Database.manage_full_sweep(0,_.None)"> How can I achieve that the method is rescheduled? I want it rescheduled every 5 minutes. BTW the frequency is set to 5 minutes! Regards Florian Reiser