Dialogue tree crash

hi so i have been trying to make a game and i want dialogue trees i of course didnt know how to so i looked at a tutorial this one- https://www.youtube.com/watch?v=AggBlhV6O4o
i checked how it would look and it gave me this crash

and my code was the same as the persons code and i looked around and could not find anything that was the same as mine can someone help if any extra pictures are required here is my code

my fault it messed up when i uploaded the pic

ight so the issue is some what resolved but the crash still shows

okay finally it worked idk what the issue was but i just created two new dialogue trees and it worked the second dialogue tree i made just had the crash error even though it worked glad thats over