I had the same problem, but for some reason, the following helped...
Go to your listings page.
Click on the empty square just underneath the title (an example of my title is: 2 LISTINGS) on the left hand side of the page.
When you click that button, a box should appear in the right hand corner that says EDIT SELECTED.
Click that button, and make some changes there.
I realize it won't have all of the options here, however, once you make them, and press DONE, remain on that page, and click directly onto one of your listings.
NOW, you should be able to go under amenties, make your changes, and SAVE them.
Not sure why this worked for me, but it did. Hope it helps you guys!