Can't retrieve entity config: core/store_group

#0 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/code/core/Mage/Core/Model/Resource.php(135): Mage::throwException('Can't retrieve ...')
#1 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/code/core/Mage/Core/Model/Mysql4/Abstract.php(222): Mage_Core_Model_Resource->getTableName('core/store_grou...')
#2 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/code/core/Mage/Core/Model/Mysql4/Abstract.php(205): Mage_Core_Model_Mysql4_Abstract->getTable('store_group')
#3 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/code/core/Mage/Core/Model/Mysql4/Collection/Abstract.php(77): Mage_Core_Model_Mysql4_Abstract->getMainTable()
#4 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/code/core/Mage/Core/Model/Mysql4/Collection/Abstract.php(63): Mage_Core_Model_Mysql4_Collection_Abstract->_initSelect()
#5 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/code/core/Mage/Core/Model/Config.php(697): Mage_Core_Model_Mysql4_Collection_Abstract->__construct(Object(Mage_Core_Model_Mysql4_Store_Group))
#6 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/code/core/Mage/Core/Model/Config.php(737): Mage_Core_Model_Config->getModelInstance('core_mysql4/sto...', Object(Mage_Core_Model_Mysql4_Store_Group))
#7 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/Mage.php(322): Mage_Core_Model_Config->getResourceModelInstance('core/store_grou...', Object(Mage_Core_Model_Mysql4_Store_Group))
#8 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/code/core/Mage/Core/Model/Abstract.php(185): Mage::getResourceModel('core/store_grou...', Object(Mage_Core_Model_Mysql4_Store_Group))
#9 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/code/core/Mage/Core/Model/Abstract.php(190): Mage_Core_Model_Abstract->getResourceCollection()
#10 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/code/core/Mage/Core/Model/App.php(335): Mage_Core_Model_Abstract->getCollection()
#11 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/code/core/Mage/Core/Model/App.php(211): Mage_Core_Model_App->_initStores()
#12 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/Mage.php(404): Mage_Core_Model_App->init('default', 'store', Array)
#13 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/app/Mage.php(423): Mage::app('default', 'store', Array)
#14 /home/httpd/vhosts/kunstmuseumbasel.ch/shop2.kunstmuseumbasel.ch/index.php(40): Mage::run('default')
#15 {main}