title: Magento - Indexer model is not defined
body: <p>After installing the <strong>Activo Advanced Search Extension for Magento</strong> we get this error:</p>
  
  <p>Indexer model is not defined.</p>
  
  <p>Trace:</p>
  
  <pre><code>#0 httpdocs/app/code/core/Mage/Index/Model/Process.php(309): Mage::throwException('Indexer model i...')
  
  #1 httpdocs/app/code/core/Mage/Index/Block/Adminhtml/Notifications.php(41): Mage_Index_Model_Process-&gt;getIndexer()
  
  #2 httpdocs/app/design/adminhtml/default/default/template/index/notifications.phtml(27): Mage_Index_Block_Adminhtml_Notifications-&gt;getProcessesForReindex()
  
  #3 httpdocs/app/code/core/Mage/Core/Block/Template.php(241): include('/var/www/vhosts...')
  
  #4 httpdocs/app/code/core/Mage/Core/Block/Template.php(272): Mage_Core_Block_Template-&gt;fetchView('adminhtml/defau...')
  
  #5 httpdocs/app/code/core/Mage/Core/Block/Template.php(286): Mage_Core_Block_Template-&gt;renderView()
  
  #6 httpdocs/app/code/core/Mage/Adminhtml/Block/Template.php(81): Mage_Core_Block_Template-&gt;_toHtml()
  
  #7 httpdocs/app/code/core/Mage/Index/Block/Adminhtml/Notifications.php(67): Mage_Adminhtml_Block_Template-&gt;_toHtml()
  
  #8 httpdocs/app/code/core/Mage/Core/Block/Abstract.php(919): Mage_Index_Block_Adminhtml_Notifications-&gt;_toHtml()
  
  #9 httpdocs/app/code/core/Mage/Core/Block/Text/List.php(43): Mage_Core_Block_Abstract-&gt;toHtml()
  
  #10 httpdocs/app/code/core/Mage/Core/Block/Abstract.php(919): Mage_Core_Block_Text_List-&gt;_toHtml()
  
  #11 httpdocs/app/code/core/Mage/Core/Block/Abstract.php(637): Mage_Core_Block_Abstract-&gt;toHtml()
  
  #12 httpdocs/app/code/core/Mage/Core/Block/Abstract.php(581): Mage_Core_Block_Abstract-&gt;_getChildHtml('notifications', true)
  
  #13 httpdocs/app/design/adminhtml/default/default/template/page.phtml(55): Mage_Core_Block_Abstract-&gt;getChildHtml('notifications')
  
  #14 httpdocs/app/code/core/Mage/Core/Block/Template.php(241): include('/var/www/vhosts...')
  
  #15 httpdocs/app/code/core/Mage/Core/Block/Template.php(272): Mage_Core_Block_Template-&gt;fetchView('adminhtml/defau...')
  
  #16 httpdocs/app/code/core/Mage/Core/Block/Template.php(286): Mage_Core_Block_Template-&gt;renderView()
  
  #17 httpdocs/app/code/core/Mage/Adminhtml/Block/Template.php(81): Mage_Core_Block_Template-&gt;_toHtml()
  
  #18 httpdocs/app/code/core/Mage/Core/Block/Abstract.php(919): Mage_Adminhtml_Block_Template-&gt;_toHtml()
  
  #19 httpdocs/app/code/core/Mage/Core/Model/Layout.php(555): Mage_Core_Block_Abstract-&gt;toHtml()
  
  #20 httpdocs/app/code/core/Mage/Core/Controller/Varien/Action.php(390): Mage_Core_Model_Layout-&gt;getOutput()
  
  #21 httpdocs/app/code/core/Mage/Adminhtml/controllers/DashboardController.php(43): Mage_Core_Controller_Varien_Action-&gt;renderLayout()
  
  #22 httpdocs/app/code/core/Mage/Core/Controller/Varien/Action.php(418): Mage_Adminhtml_DashboardController-&gt;indexAction()
  
  #23 httpdocs/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(250): Mage_Core_Controller_Varien_Action-&gt;dispatch('index')
  
  #24 httpdocs/app/code/core/Mage/Core/Controller/Varien/Front.php(172): Mage_Core_Controller_Varien_Router_Standard-&gt;match(Object(Mage_Core_Controller_Request_Http))
  
  #25 httpdocs/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Controller_Varien_Front-&gt;dispatch()
  
  #26 httpdocs/app/Mage.php(684): Mage_Core_Model_App-&gt;run(Array)
  
  #27 httpdocs/index.php(87): Mage::run('', 'store')
  
  #28 {main}
  
  Error log record number: 597672822834 
  </code></pre>
  
  <p>I've tried disabling APC, Memcached and Varnish but this doesn't make a difference. Also checked the permissions but everything appears to be installing correctly.</p>
  
  <p>Also tried the install via Magento Connect and done a manual install but still no joy.</p>
  
  <p>Any idea's on this?
  Cheers
  Steve</p>