Notice: Undefined index: frontend  in /opt/MGK/MAGENTO/html-magento-prod-v1.9-2018-09-10/app/code/community/Magestore/Bannerslider/controllers/IndexController.php on line 169

#0 /opt/MGK/MAGENTO/html-magento-prod-v1.9-2018-09-10/app/code/community/Magestore/Bannerslider/controllers/IndexController.php(169): mageCoreErrorHandler(8, 'Undefined index...', '/opt/MGK/MAGENT...', 169, Array)
#1 /opt/MGK/MAGENTO/html-magento-prod-v1.9-2018-09-10/app/code/community/Magestore/Bannerslider/controllers/IndexController.php(85): Magestore_Bannerslider_IndexController->getUserCode(NULL)
#2 /opt/MGK/MAGENTO/html-magento-prod-v1.9-2018-09-10/app/code/core/Mage/Core/Controller/Varien/Action.php(418): Magestore_Bannerslider_IndexController->impressAction()
#3 /opt/MGK/MAGENTO/html-magento-prod-v1.9-2018-09-10/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(254): Mage_Core_Controller_Varien_Action->dispatch('impress')
#4 /opt/MGK/MAGENTO/html-magento-prod-v1.9-2018-09-10/app/code/core/Mage/Core/Controller/Varien/Front.php(172): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#5 /opt/MGK/MAGENTO/html-magento-prod-v1.9-2018-09-10/app/code/core/Mage/Core/Model/App.php(365): Mage_Core_Controller_Varien_Front->dispatch()
#6 /opt/MGK/MAGENTO/html-magento-prod-v1.9-2018-09-10/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#7 /opt/MGK/MAGENTO/html-magento-prod-v1.9-2018-09-10/index.php(108): Mage::run('', 'store')
#8 {main}