Dani,
The Login button change is a problem Facebook introduced yesterday with an update to their Javascript API. There are multiple bugs submitted to Facebook regarding these issues, and we're hoping they will be fixed later today. For more information on some of the problems our users have encountered, please see the thread below:
www.sourcecoast.com/forums/jfbconnect/jf...mysteriously-changed
Specifically, the bug you mention you are having is listed below:
developers.facebook.com/bugs/256345417806493
I'd *highly* recommend using the "Does this repro describe your problem" link and click "Yes". Give information about your site and other details requested. Then, comment in the bottom saying "This is happening to me too". The more people that do that, the higher the visibility the problem becomes for Facebook. This is an issue they will have to fix, and the louder bugs get more attention.
Hope that helps, and sorry for the troubles!
Alex