My background: I'm an absolute novice when it comes Magento, although quite familiar with PHP/MySQL. I work for a hosting company in technical support now.
Problem: I just transferred a large Magento 1.8.1.0 site from one server to another. Following the move, whenever a customer logs in they get the following error:
Item (Webtex_CustomerGroupsPrice_Model_Catalog_Product) with the same id "1518" already exist
Trace:
#0 /home/thecarat/public_html/app/code/core/Mage/Eav/Model/Entity/Collection/Abstract.php(265): Varien_Data_Collection->addItem(Object(Webtex_CustomerGroupsPrice_Model_Catalog_Product))
#1 /home/thecarat/public_html/app/code/core/Mage/Eav/Model/Entity/Collection/Abstract.php(1057): Mage_Eav_Model_Entity_Collection_Abstract->addItem(Object(Webtex_CustomerGroupsPrice_Model_Catalog_Product))
#2 /home/thecarat/public_html/app/code/core/Mage/Eav/Model/Entity/Collection/Abstract.php(871): Mage_Eav_Model_Entity_Collection_Abstract->_loadEntities(false, false)
#3 /home/thecarat/public_html/app/code/core/Mage/Catalog/Helper/Product/Compare.php(214): Mage_Eav_Model_Entity_Collection_Abstract->load()
#4 /home/thecarat/public_html/app/design/frontend/base/default/template/catalog/product/compare/sidebar.phtml(30): Mage_Catalog_Helper_Product_Compare->getItemCollection()
#5 /home/thecarat/public_html/app/code/core/Mage/Core/Block/Template.php(241): include('/home/thecarat/...')
#6 /home/thecarat/public_html/app/code/core/Mage/Core/Block/Template.php(272): Mage_Core_Block_Template->fetchView('frontend/base/d...')
#7 /home/thecarat/public_html/app/code/core/Mage/Core/Block/Template.php(286): Mage_Core_Block_Template->renderView()
#8 /home/thecarat/public_html/app/code/core/Mage/Core/Block/Abstract.php(919): Mage_Core_Block_Template->_toHtml()
#9 /home/thecarat/public_html/app/code/core/Mage/Core/Block/Text/List.php(43): Mage_Core_Block_Abstract->toHtml()
#10 /home/thecarat/public_html/app/code/core/Mage/Core/Block/Abstract.php(919): Mage_Core_Block_Text_List->_toHtml()
#11 /home/thecarat/public_html/app/code/core/Mage/Core/Block/Abstract.php(637): Mage_Core_Block_Abstract->toHtml()
#12 /home/thecarat/public_html/app/code/core/Mage/Core/Block/Abstract.php(581): Mage_Core_Block_Abstract->_getChildHtml('left', true)
#13 /home/thecarat/public_html/app/design/frontend/mercado/default/template/page/2columns-left.phtml(27): Mage_Core_Block_Abstract->getChildHtml('left')
#14 /home/thecarat/public_html/app/code/core/Mage/Core/Block/Template.php(241): include('/home/thecarat/...')
#15 /home/thecarat/public_html/app/code/core/Mage/Core/Block/Template.php(272): Mage_Core_Block_Template->fetchView('frontend/mercad...')
#16 /home/thecarat/public_html/app/code/core/Mage/Core/Block/Template.php(286): Mage_Core_Block_Template->renderView()
#17 /home/thecarat/public_html/app/code/core/Mage/Core/Block/Abstract.php(919): Mage_Core_Block_Template->_toHtml()
#18 /home/thecarat/public_html/app/code/core/Mage/Core/Model/Layout.php(555): Mage_Core_Block_Abstract->toHtml()
#19 /home/thecarat/public_html/app/code/core/Mage/Core/Controller/Varien/Action.php(390): Mage_Core_Model_Layout->getOutput()
#20 /home/thecarat/public_html/app/code/core/Mage/Customer/controllers/AccountController.php(115): Mage_Core_Controller_Varien_Action->renderLayout()
#21 /home/thecarat/public_html/app/code/core/Mage/Core/Controller/Varien/Action.php(418): Mage_Customer_AccountController->indexAction()
#22 /home/thecarat/public_html/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(250): Mage_Core_Controller_Varien_Action->dispatch('index')
#23 /home/thecarat/public_html/app/code/core/Mage/Core/Controller/Varien/Front.php(172): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#24 /home/thecarat/public_html/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Controller_Varien_Front->dispatch()
#25 /home/thecarat/public_html/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#26 /home/thecarat/public_html/index.php(87): Mage::run('wholesale', 'store')
#27 {main}
I've found similar errors reported online but the solutions don't seem to apply to this case.
Apparently there have been no changes made from an admin point of view since the server move. I can confirm it does still work OK on the old server. I took a fresh backup of the database and tried that but still no luck.
Any ideas welcome as I'm pretty much stuck on this. Thanks