Using unity 5.4, I've got ORK Framework 2.7.2, and the completed sample project downloaded. I changed it to use the New UI systen with the prefabs provided in the separate download.
In the main menu scene, I have added a Canvas, and an EventSystem so I can have my own UI in the main scene.
The Main menu is created, and works correctly. When selecting to go to the new scene, the Generated Canvas and Eventsystem is kept. But the EventSystem does not process events. Enabling/Disabling the EventSystem makes everything work again.
If this happens to you, the easiest fix is to delete your EventSystem. Everything seems to work (at least on Mac) with the generated EventSystem.