If you can't select JomSocial, it likely means that the Social Profiles - JomSocial plugin isn't enabled. Please go to the Plugin manager and enable that plugin. If it is enabled, go to the JFBConnect -> Profiles area and verify you can configure settings there or if there's an error message which may explain why the JomSocial profile plugin isn't working.
I hope that helps, but if you need more assistance, just let me know.
Thanks,
Alex