facebook tab app – Fatal error: Uncaught OAuthException-Collection of common programming errors

I have a facebook application as a page tab, it’s a mini game.

The problem is if I stay 5 min afk in the menu and than click a button to go to other page of the game I get the following error (This doesn’t happends if you click faster than 5 minutes or so):

Fatal error: Uncaught OAuthException: An active access token must be used to query information about the current user. thrown in /home/…/facebook/base_facebook.php on line 1340

Anyone know what could be the problem?