Undefined variables node, app on node/X/fridge

when i go to the Facebook tab on a node (node/%/fridge), i get this :

Notice: Undefined variable: node in fridge_post_entity_page() (line 86 of fridge_post.module).
Notice: Trying to get property of non-object in fridge_post_entity_page() (line 86 of fridge_post.module).
Notice: Undefined variable: app in fridge_post_entity_page() (line 91 of fridge_post.module).

$node should probably be $entity :). Not sure about the $app, though. the best would probably be to refactor this, because i think a very similar thing is done elsewhere.