Topic: Devise TypeError, that puzzling “can't dup NilClass” error

I am receiving the 'can't dup NilClass' error apparently from Devise and I am really stuck. I am a long time PHP dev, but new to RoR because I inherited a large RoR application running in a production Linux environment. I am trying to get the application running on my local Windows machine, having to make a few changes to the GemFile from production for windows compatibility. So far I've got the gems installed and my rails server started, but I get the error on any routes that appear to call 'authenticate_user' via the 'before_filter' command set up in the application_controller.rb. I can load some routes of the application successfully (like password_reset) that are specified by the 'except' filter shown below. I'll first summarize the environments of both instances of the app and some Gem info:

    Linux Cent 0S
    Ruby 1.9.3 r194
    rails 3.0.18
    devise 1.3.4
    warden 1.0.4
    orm_adapter 0.0.5
    rack 1.2.5
    mysql2 0.2.13
    dalli 1.1.3
    eventmachine 0.12.10
    nested_form 0.2.0
    unicorn 3.7.0 (with kgio 2.5.0, without thin)

    Windows 7 64bit
    Ruby 1.9.3 r374
    rails 3.0.18
    devise 1.3.4
    warden 1.0.6
    orm_adapter 0.0.7
    rack 1.2.8
    mysql 0.2.18
    dalli 1.1.2
    eventmachine 1.0.0
    nested_form 0.3.1
    thin 1.5.0 (without unicorn and kgio)

So the application trace seems to identify the problem here in the Devise::SessionsController on the line containing 'respond_with_navigation': TypeError at devise/sessions_controller.rb:10:in `new'

class Devise::SessionsController < ApplicationController
    prepend_before_filter :require_no_authentication, :only => [ :new, :create ]
    include Devise::Controllers::InternalHelpers

    # GET /resource/sign_in
    def new
        @messages ='sign_in').client_messages
        resource = build_resource
        respond_with_navigational(resource, stub_options(resource)){ render_with_scope :new }

and here is the top of application_controller.rb, note the :except=>[:password_reset] route, which I can load since I believe it is skipping the usage of Devise

class ApplicationController < ActionController::Base
    before_filter :authenticate_user!, :except => [:password_reset, :public_rs_list]

Unfortunately since I didn't write the app and don't have a better understanding of the application stack I cannot give more context regarding the issue, but I'm hoping someone might point me in the right direction and/or describe some common issues related to this error, FYI I did try the suggestions located here and in similar posts found in stackoverflow and via Google search, but none seemed to make a difference or perhaps I wasn't putting the fixes in the right locations.

Also if there is any more information I need to share, please advise.

Any help on this is greatly appreciated, Thanks