After magento upgrade getting an error
Fatal error: Class 'Mage_Adminhtml_Helper_Help_Mapping' not found
Solution: set proper rights to the parent folder app/code/core/Mage/Adminhtml/Helper/Help
chmod a+x app/code/core/Mage/Adminhtml/Helper/Help
chmod a+r app/code/core/Mage/Adminhtml/Helper/Help
