Like/send buttons suddenly not working properly

Hi, I have some problems with my blog I haven’t before. Two months ago the facebook plugin worked properly, but now I noticed that (even though I hadn’t updated anything) I can’t use the Like button anymore (the little dialogue windows still opens, but then closes immediately), neither the Send buttons (it says stuff like “The page at http://www.terredegliangeli.com/calamai/?p=797 could not be reached.”).
It doesn’t happen to everybody interacting with the site. Anyway I tried from a pc using Chrome and from a mac using Safari and the problem is still there.
Try this page to see by yourself if you find problems as I do… every post is the same, anyway.
I tried to upgrade the plugin but nothing happened. I still have to upgrade my wordpress version to 3.5, but sincerely I don’t understand what the matter is, as before everything was alright!

http://wordpress.org/extend/plugins/facebook/