Wordbooker is working perfect for me if I use only one WordPress user, the admin user. Then posting an article to Facebook works like a charm.
If one of the two editor users I created wants to post an article, nothing happens with Facebook. The log looks exactly the same ("Commence Publish" and "Calling wordbooker_fbclient_publishaction") but nothing arrives at Facebook. Entering the article again as the admin user and saving it again sends the article to Facebook.
I am sure it is some setting and I think I remember something when I installed Wordbooker about a year ago, but I cannot recall.
So please help, even if it is a beginner problem here. Sorry.