Thanks Otto,
I will try out your patches. I also made a quick hack on my local copy. For me it works. Still There is an error message that there exists an iFrame but this is nothing too serious because it does not get browsers to report this as an severe error (at least not yet):
Unsafe JavaScript attempt to access frame with URL <my_url> from frame with URL https://www.facebook.com/extern/login_status.php?<api_key><my_url>. Domains, protocols and ports must match.
Anyway. Thanks!
