In the FAQ, it reads: "Error 77: Problem with reading the SSL CA cert: the certificate files on the hosting server are not accessible or missing".
I am not sure what this means honestly.
I have also used Wordbooker and Facebook Page Publish plugins and have not had difficulty authorizing those plugins for posting to Facebook. What is different about this plugin than those two in terms of authorization? I'm not sure if the developer can answer this question, but perhaps other users can. That would help me identify why I am having problems.