The error your getting (if you click the error link) is:
You failed to provide a valid list of administators. You need to supply the administors using either a "fb:app_id" meta tag, or using a "fb:admins" meta tag to specify a comma-delimited list of Facebook users.
In the JFBConnect Social configuration area, Open Graph tag, can you add the following line:
That will specify the app_id for your application, as they seem to be requesting.
Finally, one other oddity on that page is url that's being generated for the OpenGraph tag:
meta property="og:url" content="http://www.isardegna.com/redriot.html?f=39b5a5eae5334b544f45541198f8f49e&type=css&gz=gz"
We generate that URL automatically, and not sure why it has the extra query parameters on it. I see you're using JCH_Optimize, which may be part of the problem. We use it on SourceCoast.com as well though, and aren't seeing the same incorrect auto-generated URL. If you're doing anything with the URLs you want to let us know about, please do.
Thanks