This may be occuring if your Facebook Settings in "Platform Application" is turned OFF.
To Turn them on:
1. Go to your computer and log into Facebook
2. Click on "Account" in top right corner
3. Select "privacy settings"
4. Down on the bottom left of "Applications and Websites," CLICK "Edit Your Settings"
5. Under "applications you use" click TURN ON ALL PLATFORM APPLICATIONS.
I had this same problem and it was because I turned off platform applications, not realize this was the root of my problem. Everyone in Tech Support at Verizon suggested I reset my phone and I was COMPLETELY against it. And even if I had it would not have worked.
So finally, after doing some research online, I came across this information and thought I'd pass it along. I am spreading the word to help others with the same problem. Hope this helps.