Hello to everybody! I just made a tool to reserve terminals in a computer lab. It has two basic functionalities: - Make a reservation (calls the method "createInObjectManager") - Cancel a reservation (calls the method "manage_delObjects") As a manager user, I can make reservations as long as I want; however, when I cancel a reservation and try to make another reservation, I get the following error: Zope Error Zope has encountered an error while publishing this resource. Error Type: AttributeError Error Value: _setObject Does anybody knows how to solve it? Thanks in advanced, Josef.