Post comment with facebook like button doesn't

问题:

Im tryng to use the XFBML implementation of the Like Button, as it is described in the facebook social plugin page

The like button appears and works fine (it asks for a confirm action, but it works ok).

When i press the like button, a new dialog comment box popups that lets me add some comment to appear to my wall. However, when i press the "post to facebook" button, nothing happens and the popup dialog remains there. Finally, the comment doesn't appear to my facebook wall.

Any help??