'There was an error opening the Backup/Synchronization preferences. Please close preferences and try again' - This message is shown in Organizer Preferences when something went wrong with authentication process. When we launch Preferences of a Organizer with Elements Services, application tries to authenticate the user with Photoshop.com servers. During this, if anything abnormal happens, this message shown. But it's simple to resolve the problem.
How to Resolve -
1. Launch Welcome Screen, Organizer or Editor.
2. Locate 'Welcome, NAME'
3. Click on it and Sign-out.
4. Sign-in again and see the change in preferences.
It should work now. If you still face the problem, please leave a comment and we shall be able to help you in some way.