This problem may not be specific to rFacebook, but when I added acts_as_facebook_user to my user model and then made a call like:
my_user.first_name
I would get an 500 internal server error. I checked the log and saw this:
CGI::Session::CookieStore::CookieOverflow
I found that if I changed the app so that it uses db sessions everything started working.
Uncomment this [...]
