500 Internal Server Error

Use of undefined constant sponsor_img_temp - assumed 'sponsor_img_temp' (this will throw an Error in a future version of PHP) (0)

#0 /var/www/html/kuopiodancefestival/libs/templates/esiintyja-hero.php(47): CM\Exception\ErrorHandler->handleError()
#1 /var/www/html/global/functions/section-functions.php(98): include('/var/www/html/k...')
#2 /var/www/html/global/functions/section-functions.php(125): outputSection()
#3 /var/www/html/kuopiodancefestival/templates/sections.php(1): outputSections()
#4 /var/www/html/CM/Template/View.php(84): include('/var/www/html/k...')
#5 /var/www/html/CM/Template/View.php(92): CM\Template\View->render()
#6 /var/www/html/CM/Engine.php(358): CM\Template\View->fetch()
#7 [internal function]: CM\Engine->_render()
#8 /var/www/html/CM/Core/Dispatcher.php(143): call_user_func_array()
#9 /var/www/html/CM/Core/Dispatcher.php(126): CM\Core\Dispatcher->invokeMethod()
#10 /var/www/html/CM/Core/Dispatcher.php(52): CM\Core\Dispatcher->execute()
#11 /var/www/html/CM/Engine.php(119): CM\Core\Dispatcher->run()
#12 /var/www/html/CM/CM.php(66): CM\Engine->__call()
#13 /var/www/html/kuopiodancefestival/controllers/ItemController.php(98): CM::__callStatic()
#14 /var/www/html/kuopiodancefestival/controllers/ItemController.php(67): ItemController::_renderItem()
#15 [internal function]: ItemController::viewItemForPermalink()
#16 /var/www/html/CM/Core/Dispatcher.php(146): call_user_func_array()
#17 /var/www/html/CM/Core/Dispatcher.php(126): CM\Core\Dispatcher->invokeMethod()
#18 /var/www/html/CM/Net/Router.php(115): CM\Core\Dispatcher->execute()
#19 /var/www/html/CM/Engine.php(315): CM\Net\Router->route()
#20 [internal function]: CM\Engine->_start()
#21 /var/www/html/CM/Core/Dispatcher.php(143): call_user_func_array()
#22 /var/www/html/CM/Core/Dispatcher.php(126): CM\Core\Dispatcher->invokeMethod()
#23 /var/www/html/CM/Core/Dispatcher.php(52): CM\Core\Dispatcher->execute()
#24 /var/www/html/CM/Engine.php(119): CM\Core\Dispatcher->run()
#25 /var/www/html/CM/CM.php(66): CM\Engine->__call()
#26 /var/www/html/kuopiodancefestival/index.php(5): CM::__callStatic()
#27 {main}