Item (Mage_Catalog_Model_Product) with the same id "175" already exist

#0 /home/officena/public_html/app/code/core/Mage/Eav/Model/Entity/Collection/Abstract.php(236): Varien_Data_Collection->addItem(Object(Mage_Catalog_Model_Product))
#1 /home/officena/public_html/app/code/core/Mage/Eav/Model/Entity/Collection/Abstract.php(972): Mage_Eav_Model_Entity_Collection_Abstract->addItem(Object(Mage_Catalog_Model_Product))
#2 /home/officena/public_html/app/code/core/Mage/Eav/Model/Entity/Collection/Abstract.php(802): Mage_Eav_Model_Entity_Collection_Abstract->_loadEntities(false, false)
#3 /home/officena/public_html/app/code/core/Mage/Catalog/Helper/Product/Compare.php(202): Mage_Eav_Model_Entity_Collection_Abstract->load()
#4 /home/officena/public_html/app/design/frontend/onp/default/template/catalog/product/compare/sidebar.phtml(39): Mage_Catalog_Helper_Product_Compare->getItemCollection()
#5 /home/officena/public_html/app/code/core/Mage/Core/Block/Template.php(235): include('/home/officena/...')
#6 /home/officena/public_html/app/code/core/Mage/Core/Block/Template.php(266): Mage_Core_Block_Template->fetchView('frontend/onp/de...')
#7 /home/officena/public_html/app/code/core/Mage/Core/Block/Template.php(280): Mage_Core_Block_Template->renderView()
#8 /home/officena/public_html/app/code/core/Mage/Core/Block/Abstract.php(758): Mage_Core_Block_Template->_toHtml()
#9 /home/officena/public_html/app/code/core/Mage/Core/Block/Text/List.php(43): Mage_Core_Block_Abstract->toHtml()
#10 /home/officena/public_html/app/code/core/Mage/Core/Block/Abstract.php(758): Mage_Core_Block_Text_List->_toHtml()
#11 /home/officena/public_html/app/code/core/Mage/Core/Block/Abstract.php(525): Mage_Core_Block_Abstract->toHtml()
#12 /home/officena/public_html/app/code/core/Mage/Core/Block/Abstract.php(476): Mage_Core_Block_Abstract->_getChildHtml('right', true)
#13 /home/officena/public_html/app/design/frontend/onp/default/template/page/2columns-right.phtml(50): Mage_Core_Block_Abstract->getChildHtml('right')
#14 /home/officena/public_html/app/code/core/Mage/Core/Block/Template.php(235): include('/home/officena/...')
#15 /home/officena/public_html/app/code/core/Mage/Core/Block/Template.php(266): Mage_Core_Block_Template->fetchView('frontend/onp/de...')
#16 /home/officena/public_html/app/code/core/Mage/Core/Block/Template.php(280): Mage_Core_Block_Template->renderView()
#17 /home/officena/public_html/app/code/core/Mage/Core/Block/Abstract.php(758): Mage_Core_Block_Template->_toHtml()
#18 /home/officena/public_html/app/code/core/Mage/Core/Model/Layout.php(529): Mage_Core_Block_Abstract->toHtml()
#19 /home/officena/public_html/app/code/core/Mage/Core/Controller/Varien/Action.php(391): Mage_Core_Model_Layout->getOutput()
#20 /home/officena/public_html/app/code/core/Mage/Cms/Helper/Page.php(130): Mage_Core_Controller_Varien_Action->renderLayout()
#21 /home/officena/public_html/app/code/core/Mage/Cms/Helper/Page.php(52): Mage_Cms_Helper_Page->_renderPage(Object(Mage_Cms_IndexController), 'no-route')
#22 /home/officena/public_html/app/code/core/Mage/Cms/controllers/IndexController.php(75): Mage_Cms_Helper_Page->renderPage(Object(Mage_Cms_IndexController), 'no-route')
#23 /home/officena/public_html/app/code/core/Mage/Core/Controller/Varien/Action.php(420): Mage_Cms_IndexController->noRouteAction()
#24 /home/officena/public_html/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(253): Mage_Core_Controller_Varien_Action->dispatch('noRoute')
#25 /home/officena/public_html/app/code/core/Mage/Core/Controller/Varien/Front.php(176): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#26 /home/officena/public_html/app/code/core/Mage/Core/Model/App.php(340): Mage_Core_Controller_Varien_Front->dispatch()
#27 /home/officena/public_html/app/Mage.php(627): Mage_Core_Model_App->run(Array)
#28 /home/officena/public_html/index.php(80): Mage::run('', 'store')
#29 {main}