App.Store vs App.store

I created my Store as App.store and everything worked fine. Later on I went and renamed it to App.Store and that gave me an error:

Uncaught TypeError: Object [object Object] has no method ‘create’ ----- ember-1.0.0-rc.3.js:6854

Is there a specific reason that this is happening? Is Ember interpreting that as a class and not an instance?

I figured out my problem, I was using DS.Store.create, instead of extend. My problem went away once I fixed that.