Can't View Collections

Hi all,

These same errors are thrown each time I click on a link to a collection - I'm not adept enough to know what they refer to, other than noting that Zend is referenced many times - anyone have a magic bullet?:

#0 /d1/spcollsite/online-exhibits/delatorre/application/helpers/ItemFunctions.php(360): get_current_item()
#1 /d1/spcollsite/online-exhibits/delatorre/application/views/scripts/collections/show.php(6): item_has_thumbnail()
#2 /d1/spcollsite/online-exhibits/delatorre/application/libraries/Omeka/View.php(113): include('/d1/spcollsite/...')
#3 /d1/spcollsite/online-exhibits/delatorre/application/libraries/Zend/View/Abstract.php(888): Omeka_View->_run('/d1/spcollsite/...')
#4 /d1/spcollsite/online-exhibits/delatorre/application/libraries/Zend/Controller/Action/Helper/ViewRenderer.php(900): Zend_View_Abstract->render('collections/sho...')
#5 /d1/spcollsite/online-exhibits/delatorre/application/libraries/Zend/Controller/Action/Helper/ViewRenderer.php(921): Zend_Controller_Action_Helper_ViewRenderer->renderScript('collections/sho...', NULL)
#6 /d1/spcollsite/online-exhibits/delatorre/application/libraries/Zend/Controller/Action/Helper/ViewRenderer.php(960): Zend_Controller_Action_Helper_ViewRenderer->render()
#7 /d1/spcollsite/online-exhibits/delatorre/application/libraries/Zend/Controller/Action/HelperBroker.php(277): Zend_Controller_Action_Helper_ViewRenderer->postDispatch()
#8 /d1/spcollsite/online-exhibits/delatorre/application/libraries/Zend/Controller/Action.php(527): Zend_Controller_Action_HelperBroker->notifyPostDispatch()
#9 /d1/spcollsite/online-exhibits/delatorre/application/libraries/Zend/Controller/Dispatcher/Standard.php(295): Zend_Controller_Action->dispatch('showAction')
#10 /d1/spcollsite/online-exhibits/delatorre/application/libraries/Zend/Controller/Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#11 /d1/spcollsite/online-exhibits/delatorre/application/libraries/Zend/Application/Bootstrap/Bootstrap.php(97): Zend_Controller_Front->dispatch()
#12 /d1/spcollsite/online-exhibits/delatorre/application/libraries/Zend/Application.php(366): Zend_Application_Bootstrap_Bootstrap->run()
#13 /d1/spcollsite/online-exhibits/delatorre/application/libraries/Omeka/Core.php(165): Zend_Application->run()
#14 /d1/spcollsite/online-exhibits/delatorre/index.php(28): Omeka_Core->run()
#15 {main}

Is there an additional message that comes out just before this trace? What's here is a list of what the application was doing, but generally the actual error that caused the problem appears above this kind of trace.

Ooops - sorry, thought I'd included it:

'Exception
An item has not been set to be displayed on this theme page! Please see Omeka documentation for details.'

The collections and items are all set to Public and Featured - I don't readily see any other settings that would apply to display - of course I might be totally overlooking something...