My FAILED Update! (Don't worry, I reverted back to the original.)

Guys, IDK what to say. I realized that not all keyboards have the page up/down buttons on them so I tried to remove those controls from my game. It gave me an error when I uploaded it! I did what it told me to do in the error and it told me to REVERSE WHAT I JUST DID. If you have to know, I was turning on/off exceptions in unity. I'm new to coding so I don't know what those are, so if someone could help me that'd be nice. Please go here to comment on this project:

https://scratch.mit.edu/projects/393431403