Controller needs error

[QuantumKing]

I have this:

App = Ember.Application.create({
  Socket: EmberSockets.extend({
    host: window.location.hostname,
    port: window.location.port,
    secure: window.location.protocol === 'https:',
    controllers: ['patientsIndex', 'patient'],
    autoConnect: true
  })
});

Each controller has a "needs: ['patients']". This causes an error:

Uncaught Error: <App.PatientsIndexController:ember484> needs [ controller:patients ] but it could not be found.

How do I get around this?