Unable to see Admin collection Panel

Version: Omeka-2.1.3
Issue: unable to access the admin collection panel
From: admin Dashboard
As: admin superuser
Action: Click on Collections in the left sidebar
Result:

#0 mysite/application/models/Mixin/ElementText.php(213): Mixin_ElementText->getElement('Dublin Core', 'Contributor')
#1 mysite/application/models/Mixin/ElementText.php(736): Mixin_ElementText->getElementTexts('Dublin Core', 'Contributor')
#2 mysite/application/models/Mixin/ElementText.php(724): Mixin_ElementText->getElementTextCount('Dublin Core', 'Contributor')
#3 [internal function]: Mixin_ElementText->hasElementText('Dublin Core', 'Contributor')
#4 mysite/application/libraries/Omeka/Record/AbstractRecord.php(251): call_user_func_array(Array, Array)
#5 mysite/application/libraries/Omeka/Record/AbstractRecord.php(210): Omeka_Record_AbstractRecord->delegateToMixins('hasElementText', Array)
#6 mysite/application/models/Collection.php(142): Omeka_Record_AbstractRecord->__call('hasElementText', Array)
#7 mysite/application/models/Collection.php(142): Collection->hasElementText('Dublin Core', 'Contributor')
#8 mysite/admin/themes/default/collections/browse.php(46): Collection->hasContributor()
#9 mysite/application/libraries/Omeka/View.php(117): include('/var/www/html/_...')
#10 mysite/application/libraries/Zend/View/Abstract.php(888): Omeka_View->_run('/var/www/html/_...')
#11 mysite/application/libraries/Zend/Controller/Action/Helper/ViewRenderer.php(900): Zend_View_Abstract->render('collections/bro...')
#12 mysite/application/libraries/Zend/Controller/Action/Helper/ViewRenderer.php(921): Zend_Controller_Action_Helper_ViewRenderer->renderScript('collections/bro...', NULL)
#13 mysite/application/libraries/Zend/Controller/Action/Helper/ViewRenderer.php(960): Zend_Controller_Action_Helper_ViewRenderer->render()
#14 mysite/application/libraries/Zend/Controller/Action/HelperBroker.php(277): Zend_Controller_Action_Helper_ViewRenderer->postDispatch()
#15 mysite/application/libraries/Zend/Controller/Action.php(527): Zend_Controller_Action_HelperBroker->notifyPostDispatch()
#16 mysite/application/libraries/Zend/Controller/Dispatcher/Standard.php(308): Zend_Controller_Action->dispatch('browseAction')
#17 mysite/application/libraries/Zend/Controller/Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#18 mysite/application/libraries/Zend/Application/Bootstrap/Bootstrap.php(97): Zend_Controller_Front->dispatch()
#19 mysite/application/libraries/Zend/Application.php(366): Zend_Application_Bootstrap_Bootstrap->run()
#20 mysite/application/libraries/Omeka/Application.php(79): Zend_Application->run()
#21 mysite/admin/index.php(28): Omeka_Application->run()
#22 {main}

There should be a message about the particular error just before the trace you gave. Could you add that, too?

Thanks for the quick response. I am new to Omeka, so the error might be mine, but I am unable to fix it so far.
thanks.
The message above the trace was:
Omeka has encountered an error
Omeka_Record_Exception
There is no element "Dublin Core", "Contributor"!

That is unusual -- at first glance it looks like Omeka's element sets weren't installed correctly, or somehow got deleted.

Could you check from admin dashboard -> Settings -> Element Sets, try to edit the Dublin Core element set, and see if Contributor is listed as one of the elements

That was the first place I looked, and the Contributor item is not there.This is what I have: I made no changes:
Title, Description, Creator, Source, Rights, Coverage, BeginDate, End Date, Circa?, Primary, New Relation.

I probably should just reload my backup database?

Reloaded the sql, but nothing changed!

Yeah, that's definitely not what it should look like. Possibly something wrong with the sql being imported? Hard to tell, unfortunately.

It might work to make a separate, clean install of Omeka, then export from that just the element table to import into the new installation over the existing table.

That _might_ do it, but if there are other things wrong with the backup, anything could happen.

Hi Patrick,
I looked at the table and found the Contributor filed under a different element_set_id. The 1.5.3 elements table on this site has two additional columns added to it. This issue will undoubtedly come back to bite me. But for now I am able to access the Admin Collections. Thanks for your help. K.