title: Facebook App : Invalid OAuth 2.0 Access Token
body: <p>I am almost done building a facebook application.
  Its working alright but for one problem.
  If a user adds the application to his profile for the first time ( by granting appropriate permissions ) it works fine. But when user removes the application from his Application Settings and then tries to add the application again, it just won't work !
  When i try to do user.hasAppPermission to check if user has granted appropriate permission to the application, the call throws "Invalid OAuth 2.0 Access Token" exception. I am just clueless why this is happening. I am using PHP-SDK for facebook. The permissions i ask for : "publish_stream" and "email".
  Need a slight push in right direction.</p>
  
  <p>Thanks.</p>