Problem in the rubyonrails getting started tutorial

Hello,

I was just working my way pretty carefully through the getting started
tutorial and I've hit an unusual snag that I can't make any sense of.
After adding the authenticate before filter to my posts controller I
was presented with this error message:

Routing Error

undefined method `Â Â before_filter' for PostsController:Class

If I delete the line that contains the before_filter then everything
works as expected, minus authentication of course. The authenticate
method is this:

  private

  def authenticate
    authenticate_or_request_with_http_basic do |user_name, password|
      user_name == 'admin' && password == 'password'
    end
  end

And the before_filter line is this:

before_filter :authenticate, :except => [:index, :show]

If anybody can tell me what is going on I would be very appreciative.
The getting started tutorial that I am referring to is here:
http://guides.rubyonrails.org/getting_started.html
Thanks,
ashleigh

Perhaps you have some non-printing characters at the start of the
line. What happens if you type it in again? Also check the line
before.

If that does not fix it show us the stack dump and the complete error
message. Also the code around the error.

Colin

As a test, I would place the before_filter in the Application Controller
to ensure it's working. If you don't receive an error, then do as Colin
suggested above.

If you do, post the error as instructed above.

In the test within the application controller just put:

before_filter :authenticate

.. and comment out the other before_filters in your other controllers.