Undefined path method for nil: NilClass using chargify_api_ares gem

It seems to me that this should be a simple problem, but I draw out my hair, trying to track them. I set the gem chargify_api_ares, but I can not even do such basic things as

Chargify::Subscription.create

How do I get this error path. I feel that this must be a problem with gems, but I don’t know where to go from here.

UPDATE: The batch show chargify_api_ares shows the correct path, I just somehow cannot access it. Still trying random environmental things.

This seems to be the source of the problem, in active_resource \ base.rb:

# Gets the \prefix for a resource nested URL (e.g., <tt>prefix/collectionname/1.json</tt>)
      # This method is regenerated at runtime based on what the \prefix is set to.
      def prefix(options={})
        default = site.path
        default << '/' unless default[-1..-1] == '/'
        # generate the actual method based on the current site path
        self.prefix = default
        prefix(options)
      end

, Chargify.subdomain site.path, , activeresource , .