My team is in charge of some difficulties with an app on Facebook. We believe this occurred some error in loading the iframe. We discovered this error through Firebug:
I got the same issue, and it got fixed, when i used target="_top" for the link , and it is now working perfectly.
Thank you
This has been reported here : http://developers.facebook.com/bugs/531093333589159?browse=search_51217726097663989102940
I believe there is not much we can do but wait for a fix. Have the same issue with the "FB Share" plugin.
Use this line given below instead of header() function.
echo "<script>window.top.location = 'https://apps.facebook.com/yourappnamespace/';</script>";