Hallo there,
I have a similar problem: The site at our staging server (where we test this) is at:
www.sintagewpareas.gr/
The problem (as above stated) is that when I click on the "login with facebook" button (it is located at the right column), I get nothing. A pop up window opens, but nothing happens.
The first time it asked for a username/pass for facebook, but even then, nothing happened.
Any insights into what I have setup wrong?
(Possibly relevant) info: I have both kunena and CB on that site, and I have installed both the plugins for that.
Thanks
Konstantinos