Can you go to Facebook.com and then into your users Settings -> Apps -> <Your App> and verify the permissions you've granted to your website? You should have the "Post" permission listed there.
If that's there, then please make sure that the status update you're creating in JomSocial is set to 'public'. Otherwise, JFBConnect will not push it.
Finally, I know you have had a JFBC subscription for quite some time. Has this feature ever worked and just stopped, or is this the first time you're setting it up? That will help narrow things down as well.
I hope that helps, but if not, let us know.
Thanks,
Alex