Facebook invite friends error: Sorry, your request could not be processed

I have the following code to allow users to invite thier Facebook friends:

function create_fb_friends() {
  FB.init({
    appId  : 'xxxxxxx',
    status : true, // check login status
    cookie : true, // enable cookies to allow the server to a开发者_JAVA技巧ccess the session
    xfbml  : true  // parse XFBML
 });

FB.ui({
    method: 'fbml.dialog',
    fbml: (
      '<fb:request-form action="/" target="_top"\
                  method="POST"\
                  invite="true"\
                  type="MyApp Application"\
                  content="Checkout this new application.">\
                  <fb:multi-friend-selector\
                  showborder="false"\
                  actiontext="Invite friends to...">\
                  </fb:request-form>'
       ),
    size: {width:640,height:480}, width:640, height:480
  });
}

When I click on send invitation, I get only an error from Facebook:

Sorry, your request could not be processed.

Please try again

I do not have any clue where the problem could be, since there is not a real feedback in the error.

It seems as though this is a known problem: http://bugs.developers.facebook.net/show_bug.cgi?id=10874

Unfortunately it has been open for ages with no real feedback / action.

Side note - that error seems to point to a problem with the 'action' parameter. I replaced the URL's I was using with URL's shortened by bit.ly and it seems to be working.

Another thing the fb:multi-friend-selector is on its way out now and will no longer be available as mentioned here.

https://developers.facebook.com/docs/reference/fbml/multi-friend-selector/

Just using the example on this page would do. https://developers.facebook.com/docs/reference/dialogs/requests/