Can't get data from facebook.
Probable causes listed below:
1. Provided URL may not be valid. Make sure that the url can be opened in a web browser while logged out from Facebook. If it's an url to a personal facebook account only the account holder can get the public url from the bottom (near footer) of the album page. If it's a fanpage album make sure there's no age restriction on page settings.
2. It might also be a problem with CURL library or your server config