The error you're running into is an issue with the v5.2.2 release. Once the error occurs, you'll need to logout of the admin area and log back in to clear your session data. Then, go directly to the Usermap area. Don't use the dropdown filter and don't use the social network icons on the main JFBConnect admin page (which preset the filters).
If you want to make a minor code change that will fix the error completely, please see
this post
.
Sorry for the trouble. That problem will be fixed in the upcoming release, due out in about a week.
Thanks,
Alex