Item (Mage_Catalog_Model_Category) with the same id "9" already exist

#0 /var/www/html/app/code/core/Mage/Eav/Model/Entity/Collection/Abstract.php(265): Varien_Data_Collection->addItem(Object(Mage_Catalog_Model_Category))
#1 /var/www/html/app/code/core/Mage/Eav/Model/Entity/Collection/Abstract.php(1057): Mage_Eav_Model_Entity_Collection_Abstract->addItem(Object(Mage_Catalog_Model_Category))
#2 /var/www/html/app/code/core/Mage/Eav/Model/Entity/Collection/Abstract.php(871): Mage_Eav_Model_Entity_Collection_Abstract->_loadEntities(false, false)
#3 /var/www/html/app/code/core/Mage/Catalog/Model/Resource/Category/Collection.php(225): Mage_Eav_Model_Entity_Collection_Abstract->load(false, false)
#4 /var/www/html/app/code/core/Mage/Catalog/Model/Resource/Category.php(660): Mage_Catalog_Model_Resource_Category_Collection->load()
#5 /var/www/html/app/code/core/Mage/Catalog/Model/Category.php(839): Mage_Catalog_Model_Resource_Category->getChildrenCategories(Object(Mage_Catalog_Model_Category))
#6 /var/www/html/app/design/frontend/rwd/levanilla/template/page/html/custommenu_responsive.phtml(33): Mage_Catalog_Model_Category->getChildrenCategories()
#7 /var/www/html/app/code/core/Mage/Core/Block/Template.php(241): include('/var/www/html/a...')
#8 /var/www/html/app/code/core/Mage/Core/Block/Template.php(272): Mage_Core_Block_Template->fetchView('frontend/rwd/le...')
#9 /var/www/html/app/code/core/Mage/Core/Block/Template.php(286): Mage_Core_Block_Template->renderView()
#10 /var/www/html/app/code/core/Mage/Core/Block/Abstract.php(923): Mage_Core_Block_Template->_toHtml()
#11 /var/www/html/app/design/frontend/rwd/levanilla/template/page/html/header.phtml(149): Mage_Core_Block_Abstract->toHtml()
#12 /var/www/html/app/code/core/Mage/Core/Block/Template.php(241): include('/var/www/html/a...')
#13 /var/www/html/app/code/core/Mage/Core/Block/Template.php(272): Mage_Core_Block_Template->fetchView('frontend/rwd/le...')
#14 /var/www/html/app/code/core/Mage/Core/Block/Template.php(286): Mage_Core_Block_Template->renderView()
#15 /var/www/html/app/code/core/Mage/Core/Block/Abstract.php(923): Mage_Core_Block_Template->_toHtml()
#16 /var/www/html/app/code/core/Mage/Core/Block/Abstract.php(641): Mage_Core_Block_Abstract->toHtml()
#17 /var/www/html/app/code/core/Mage/Core/Block/Abstract.php(585): Mage_Core_Block_Abstract->_getChildHtml('header', true)
#18 /var/www/html/app/design/frontend/rwd/levanilla/template/page/2columns-left.phtml(49): Mage_Core_Block_Abstract->getChildHtml('header')
#19 /var/www/html/app/code/core/Mage/Core/Block/Template.php(241): include('/var/www/html/a...')
#20 /var/www/html/app/code/core/Mage/Core/Block/Template.php(272): Mage_Core_Block_Template->fetchView('frontend/rwd/le...')
#21 /var/www/html/app/code/core/Mage/Core/Block/Template.php(286): Mage_Core_Block_Template->renderView()
#22 /var/www/html/app/code/core/Mage/Core/Block/Abstract.php(923): Mage_Core_Block_Template->_toHtml()
#23 /var/www/html/app/code/core/Mage/Core/Model/Layout.php(555): Mage_Core_Block_Abstract->toHtml()
#24 /var/www/html/app/code/core/Mage/Core/Controller/Varien/Action.php(390): Mage_Core_Model_Layout->getOutput()
#25 /var/www/html/app/code/local/OneThemes/Blog/Helper/Post.php(40): Mage_Core_Controller_Varien_Action->renderLayout()
#26 /var/www/html/app/code/local/OneThemes/Blog/controllers/PostController.php(162): OneThemes_Blog_Helper_Post->renderPage(Object(OneThemes_Blog_PostController), 'Coffe-combines-...')
#27 /var/www/html/app/code/core/Mage/Core/Controller/Varien/Action.php(418): OneThemes_Blog_PostController->viewAction()
#28 /var/www/html/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(254): Mage_Core_Controller_Varien_Action->dispatch('view')
#29 /var/www/html/app/code/core/Mage/Core/Controller/Varien/Front.php(172): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#30 /var/www/html/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Controller_Varien_Front->dispatch()
#31 /var/www/html/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#32 /var/www/html/index.php(89): Mage::run('', 'store')
#33 {main}