Trying to authorise my Facebook app. But I get this error message every time:

Can’t get Page Token. NO TOKEN RETURNED. Are you sure that user you are trying to authorize is an admin of the page? This message means user was authorized as profile, but page refused to return authorization token. This usually happens when user has no rights to post to that page.

I’ve followed every step of the instructions very carefully. This message comes after clicking “Authorize Your Facebook Account at step 3.2, after the wizard screens.

Clearly the problem is something to do with how I am set up as a user on the page, but can you suggest what? I am the person who created the FB app, and have the role “Administrator”.