Wow. I was just about to search for that very phrase, when I noticed Fred has asked this question, just earlier today.
Actually, I have a double problem. What I am trying to do is to put a list of an FB logged-in user's friends on the site, so that they can choose which friends they want to inform about our site. I would have thought that this would have been a common and easy option to use with JFBConnect.
If I click the link created by the tag {JFBCRequest request_id=1 link_text=Invite Friends}, I get 'The parameter app_id is required'.
The request with the id of 1 appears to be configured correctly (although I am just a newbie at this). The app_id is filled in in the FB configuration tab, along with the secret code. All seems to me to be in order.
BTW: If I add the app_id as {JFBCRequest request_id=1 app_id=<my app id> link_text=Invite Friends} - (where <my app id> is the actual id number) - I still get 'The parameter app_id is required', so that doesn't work.
The URL of the pop-up shows a missing app_id, whatever I try - i.e. parameters sent to
www.facebook.com/v2.4/dialog/apprequests always show up as ?app_id=&data=1&display=popup..... etc.
So I tried adding the app_id into the url of the pop-up and pasting it into a normal browser tab, just to see what happens but then I get 'Game Requests are only available to games.', which appears to be a nonsensical error message.
So can I be told what I am doing wrong, please?