PHP Error [8]

Undefined index: events_id (/home/docando/public_html/app/modules/events/events.php:16)

#0 /home/docando/public_html/core/Router.php(78): Page->__construct()
#1 /home/docando/public_html/core/App.php(21): Router->start()
#2 /home/docando/public_html/index.php(19): App->start()