problem with enemy

Hello i am trying to make enemy follow player and maybe after that enemy healt. I have learned unreal tutorial about behavior tree https://docs.unrealengine.com/latest/INT/Engine/AI/BehaviorTrees/QuickStart/index.html , and i i have done everything, but it gives me errors, which why enemy maybe don’t follow player. All errors is about AgroCheck which is included in Behavior tree. I have attached the error picture, if someone could help me, it isn’t maybe big problem

no i don’t get these errors,when i fixed blueprint code, but enemy doesn’t follow player and behavior tree get next red error message: