I realize that this post is dead but for people that go through all the steps above, I have a very easy fix. Make sure your SS file matches the case of the page controller.

For Example:
If you are creating a contact page you would use
class ContactPage_Controller extends Page_Controller {}
That would mean your template must be titled "ContactPage.ss" and not "contactPage.ss".

I was recreating my base file (Page.ss) and used a lower-case 'p'. So I have been reading and following all of the suggestions given here and a number of other blogs and forums that have similar advice. All came back to the same thing. Solution was a capital 'P'.