I installed everything, and everything works fine. But when I fill in the facebook profile tabs, thing get weird.

I created a webform. I set the url of the View path to this webform node. When I load the page tab in facebook everything works fine. When I submit the webform, fb_tab_view() is called. the getSignedRequest has no page variable in it and the function returns an empty string.

The IFrame in the page tab goes blank (because of the empty string return) and the data from my webform is not saved.