This is due to a Facebook API change that will be going (has gone) live starting the week of December 12th.
To prevent this issue in 1.0.4 or 1.1.0, open the attachment. Go into the directory that corresponds with your version. You'll find xenforo.js. You need to upload this to the js/xenforo directory in XenForo, overwriting the version that is there. You will now be using the newer Facebook API for auth.
If you applied the fix I previously posted and wish to overwrite it with this version, you need only follow the instructions posted above.
[Edit Dec 9, 18:05 GMT: patched JS files updated. Follow instructions above.]
To prevent this issue in 1.0.4 or 1.1.0, open the attachment. Go into the directory that corresponds with your version. You'll find xenforo.js. You need to upload this to the js/xenforo directory in XenForo, overwriting the version that is there. You will now be using the newer Facebook API for auth.
If you applied the fix I previously posted and wish to overwrite it with this version, you need only follow the instructions posted above.
[Edit Dec 9, 18:05 GMT: patched JS files updated. Follow instructions above.]