[Zope] communication between Zope's now broken

I have one complex of Zopes that have one adminsistration site and a collection of productions sites. The administration site invokes actions on in the production sites through the web using a redirect, and control is returned to the administrative site by a redirect back. It's worked pretty well. I've now cloned the site--and all the inter-zope communications no long work. If I invoke them through a browser URL, they work, but programmatically they do not. I suspect a security/permissions problem, but I've not been able to identify it. Any suggestions appreciated.