Item (Mage_Catalog_Model_Category) with the same id "454" already exist

#0 /home/mcconnel/public_html/includes/src/__default.php(32364): Varien_Data_Collection->addItem(Object(Mage_Catalog_Model_Category))
#1 /home/mcconnel/public_html/includes/src/Mango_Ajaxlist_Helper_Category.php(268): Varien_Data_Collection_Db->load()
#2 /home/mcconnel/public_html/includes/src/Mango_Ajaxlist_Model_Layer_Filter_Category.php(197): Mango_Ajaxlist_Helper_Category->getChildrenCategories(Object(Mage_Catalog_Model_Category))
#3 /home/mcconnel/public_html/includes/src/Mage_Catalog_Model_Layer_Filter_Abstract.php(151): Mango_Ajaxlist_Model_Layer_Filter_Category->_getItemsData()
#4 /home/mcconnel/public_html/includes/src/Mage_Catalog_Model_Layer_Filter_Abstract.php(120): Mage_Catalog_Model_Layer_Filter_Abstract->_initItems()
#5 /home/mcconnel/public_html/includes/src/Mage_Catalog_Model_Layer_Filter_Abstract.php(109): Mage_Catalog_Model_Layer_Filter_Abstract->getItems()
#6 /home/mcconnel/public_html/includes/src/Mage_Catalog_Block_Layer_Filter_Abstract.php(132): Mage_Catalog_Model_Layer_Filter_Abstract->getItemsCount()
#7 /home/mcconnel/public_html/includes/src/Mage_Catalog_Block_Layer_View.php(218): Mage_Catalog_Block_Layer_Filter_Abstract->getItemsCount()
#8 /home/mcconnel/public_html/includes/src/Mage_Catalog_Block_Layer_View.php(233): Mage_Catalog_Block_Layer_View->canShowOptions()
#9 /home/mcconnel/public_html/app/design/frontend/base/default/template/ajaxlayerednavigation/catalog/layer/view.phtml(34): Mage_Catalog_Block_Layer_View->canShowBlock()
#10 /home/mcconnel/public_html/includes/src/__default.php(3428): include('/home/mcconnel/...')
#11 /home/mcconnel/public_html/includes/src/__default.php(3459): Mage_Core_Block_Template->fetchView('frontend/base/d...')
#12 /home/mcconnel/public_html/includes/src/__default.php(3473): Mage_Core_Block_Template->renderView()
#13 /home/mcconnel/public_html/includes/src/__default.php(2617): Mage_Core_Block_Template->_toHtml()
#14 /home/mcconnel/public_html/includes/src/__default.php(13866): Mage_Core_Block_Abstract->toHtml()
#15 /home/mcconnel/public_html/includes/src/__default.php(2617): Mage_Core_Block_Text_List->_toHtml()
#16 /home/mcconnel/public_html/includes/src/__default.php(2335): Mage_Core_Block_Abstract->toHtml()
#17 /home/mcconnel/public_html/includes/src/__default.php(2279): Mage_Core_Block_Abstract->_getChildHtml('left', true)
#18 /home/mcconnel/public_html/app/design/frontend/ultimo/default/template/page/2columns-left.phtml(67): Mage_Core_Block_Abstract->getChildHtml('left')
#19 /home/mcconnel/public_html/includes/src/__default.php(3428): include('/home/mcconnel/...')
#20 /home/mcconnel/public_html/includes/src/__default.php(3459): Mage_Core_Block_Template->fetchView('frontend/ultimo...')
#21 /home/mcconnel/public_html/includes/src/__default.php(3473): Mage_Core_Block_Template->renderView()
#22 /home/mcconnel/public_html/includes/src/__default.php(2617): Mage_Core_Block_Template->_toHtml()
#23 /home/mcconnel/public_html/includes/src/__default.php(28750): Mage_Core_Block_Abstract->toHtml()
#24 /home/mcconnel/public_html/includes/src/__default.php(14259): Mage_Core_Model_Layout->getOutput()
#25 /home/mcconnel/public_html/app/code/core/Mage/Catalog/controllers/CategoryController.php(161): Mage_Core_Controller_Varien_Action->renderLayout()
#26 /home/mcconnel/public_html/includes/src/__default.php(14287): Mage_Catalog_CategoryController->viewAction()
#27 /home/mcconnel/public_html/includes/src/__default.php(18772): Mage_Core_Controller_Varien_Action->dispatch('view')
#28 /home/mcconnel/public_html/includes/src/__default.php(18302): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#29 /home/mcconnel/public_html/includes/src/__default.php(21218): Mage_Core_Controller_Varien_Front->dispatch()
#30 /home/mcconnel/public_html/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#31 /home/mcconnel/public_html/index.php(86): Mage::run('', 'store')
#32 {main}