I have an app that I cannot delete. Anyone know how to do this?

Someone sent me a script in Final Draft. I tried opening the file, it said it was corrupt and that I should delete the app and start over.

But when I tried to delete the app it said I couldn't and gave me an error code -43. My final draft worked fine until this new script was sent to me.

How do I delete the app to reinstall? Thanks for anyone's help.