Sorry you had trouble adding this goal! The only way to add a rating scale like that is on your Start page. I tried to replicate the issue, but was able to add it to your page without any issues. Since you have already tried to add it so many different ways, I left it up for you so you don't have to mess with it any more if you don't want to. So, hopefully you are all set now.
f you have trouble adding a goal like that in the future, you might want to try adding it from another browser and/or try clearing your browser's cache and cookies.
I hope this helps!