The end of that URL shows that Facebook is trying to load a scope of publish_actions. That permission was removed by Facebook in late August. JFBConnect should be requesting the new permission, publish_pages, instead.
Can you please try to:
* Edit the Channel in JFBConnect and simply hit 'save'. That should update the permissions being requested automatically
* If that doesn't work, try deleting and recreating the channel
Hopefully, either of the above will help get you going, but if you still have issues, please let us know and we'll gladly help investigate further.
Thanks,
Alex