This is a quick update to let everyone know what was happening with this particular error (I know. There are many bugs in the plugin. I hope to be able to use the ‘new’ Facebook Graph API and release the plugin as open source this summer.)
For reasons that were never explained to me, Facebook disabled this plugin. An unknown side-effect (to me, at least) was that this also disables all photos associated with the plugin. This is very troubling to me. All old photos should be reactivated now.
I will hopefully begin updating the plugin soon.