I am trying to set a cron task to read updates for a Facebook application. I have prompted the user to grant Offline Access permissions and i have store the session_key in the db.
I am crearing a new Facebook object and besides api and secret key I also use the session_key (previously stored in db) and the fb uid. When i am trying to create the auth token or do a API call i get a Error 104: Incorrect signature
Any ideas, experience, hints ?
I faced the same problem where the error displayed was:

"facebook.FacebookError: Error 104: Incorrect signature"

Just reset your APP Secret_key and make corresponding change in the code and that sgould fix the problem.
Cheers!
PyFacebook Infinite Session