In /components/com_jfbconnect/libraries/provider/facebook/channel/page.php around line 106 replace
$ids = explode("_", $pageId);
with
$ids = explode("_", $data['id']);
and the same change in /components/com_jfbconnect/libraries/provider/facebook/channel/group.php around line 81.
I'll check this in so it will be available in the next release.
-Melissa