[Zope] Can't get ZClient to work, zope 2.2.0

hit http://zope.carbonecho.com/forum/sepServe to see the error ('expecting read-only buffer...') here's the external function: from ZPublisher import Client def ServePHP(url='http://www.yahoo.com', username='bill', password='xyz'): print 'Sep Serving ' + str(url) return Client.call(url, username, password) [1]