ActiveResource does not detect errors for my very simple model

The documentation says to return a code 422 with a packet in the
following format:

<errors type="array"><error>First cannot be empty</error></errors>

So that is what I am doing. But my model will not raise an exception
on a create call that returns such a response, and a record created
that way returns true for its valid? call.

I simply do:

Menu.create

Which triggers validation errors in the other application, which
responds with 422 and the following packet, because a "name" field is
required:

<errors type="array">
  <error>Name cannot be empty</error>
</errors>

Why would ActiveResource interpret such a response as valid? Is there
something more I need to do in my model for validations to take
effect? My models themselves are dead simple:

class ApplicationResource < ActiveResource::Base
  self.site = ‘http://localhost/frontend/www/api
end

class Menu < ApplicationResource
end

Thomas

I referred to http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/67d59a432f1d98e3
and tried this with Rails 2.2.2, but got the same result. I am
guessing the issue I am experiencing is not version-specific.

Thomas