Problem With Time Attack Racer Tutorial

When I try attach “Array Element” to the “Target” it says that "Actor refeference is not compatible with CheckPointReference. But I have done everything exactly in the same way which is done in tutorial. By the way “CheckPointCleared” is an “Event Dispatcher” which is in another blueprint. Actually I have read to learn what it is but I don’t understand exactly. If “CheckPointCleared” were a function which is in another blueprint, should I cast that blueprint to acces it’s function right? I mean since it is an “Event Dispatcher” I dont have to get a reference for that blueprint? I am a bit confused guys. Please help me.

English is not my mother language so sorry for mistakes.

Edit: A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums

This is the tutorial link and that guy is making this at 10.45-10.50.