[Plugin: Simple Facebook Connect] Error: please fill the required fields (name,

I’ve been using the Simple Facebook Connect plugin by Otto and I had sucessfully implemented it on a website one month ago. However, I was working on another site and during the testing on localhost I noticed that at the moment of submitting the comment it failed throwing the error
Error: please fill the required fields (name, email).
I went to the site that had the plugin working (which I had not updated) and it was no longer working as well. Now, I this this has something to do with Facebook, some new parameters for the application or something since it’s almost impossible that a working plugin stops working just like that.
Could you give me a hand with this one? Thanks!