[Error] 
Class 'CIBlockSection' not found (0)
/home/bitrix/ext_www/lib.vrngmu.ru/conference/section.php:6
#0: include_once
	/home/bitrix/ext_www/vrngmukernel.ru/bitrix/modules/main/include/urlrewrite.php:159
#1: include_once(string)
	/home/bitrix/ext_www/vrngmukernel.ru/bitrix/urlrewrite.php:2