image_path doesn't exist in RoR 1.2.x so the call followed in view_extension.rb is not correct :

      def path_to_image(*params)
        path = super(*params) <=== HERE
        if ((in_facebook_canvas? or in_mock_ajax? or in_ajax?) and
!(/(\w+)(\:\/\/)([\w0-9\.]+)([\:0-9]*)(.*)/.match(path)))
          path = "#{request.protocol}#{request.host_with_port}#{path}"
        end
        return path
      end

Date: 2008-08-09 18:26
Sender: Gerald Bauer

FYI: The official RFacebook forum/mailing list (including
the core RFacebook developers) is @
http://groups.google.com/group/rfacebook

If you want to get the issue resolved that's the best place
to start. Cheers.

Date: 2008-06-12 09:03
Sender: Steve Jalim

Has anyone found a workaround for this yet? Would be handy to
know