En el QuickStart del ZendFramework encontré en la sección: "Create a Model and Database Table" en el bloque 7 de los code sample: en la linea 2 dice // application/model/GuestBook.php y debe ser // application/models/GuestBook.php. Eso es todo ...gracias.

<?php // application/model/GuestBook.php-> cambiar por // application/models/GuestBook.php

/** * This model class represents the business logic associated with a "guestbook" * model. While its easy to say that models are generally derived from * database tables, this is not always the case. Data sources for models are * commonly web services, the filesystem, caching systems, and more. That * said, for the purposes of this guestbook applicaiton, we have split the * buisness logic from its datasource (the dbTable). * * This particular class follows the Table Module pattern. There are other * patterns you might want to employ when modeling for your application, but * for the purposes of this example application, this is the best choice. * To understand different Modeling Paradigms: * * @see http://martinfowler.com/eaaCatalog/… [Table Module] * @see http://martinfowler.com/eaaCatalog/ [See Domain Logic Patterns and Data Source Arch. Patterns] */ class Model_GuestBook { /** Model_Table_Guestbook */