r.js optimizer build fails with 'Handlebars is not defined'

Hi, please could you help me? This is the first time I'm trying to use the require.js optimizer, so I'm probably doing something wrong, but although everything works fine with the site in development, I'm getting an error when I run

r.js -o build-config.js:

Error:

Tracing dependencies for: main
ReferenceError: Handlebars is not defined
In module tree:
    main
      router
        views/studentHomePageView
          views/toolbarView
            hbs

ReferenceError: Handlebars is not defined
In module tree:
    main
      router
        views/studentHomePageView
          views/toolbarView
            hbs

    at Object.eval (eval at <anonymous> (/usr/local/lib/node_modules/requirejs/bin/r.js:13687:38), <anonymous>:649:1)

My main.js looks like this:

require.config({

    paths: {
        backbone: 'lib/backbone-min',
        bootstrap: 'lib/bootstrap.min',
        colorbox: 'lib/jquery.colorbox',
        hammer: 'lib/hammer.min',
        Handlebars: 'lib/handlebars',
        hbs: 'lib/hbs',
        jquery: 'lib/jquery-1.9.1.min',
        jqueryhammer: 'lib/jquery.hammer',
        jqueryjpanelmenu: 'lib/jquery.jpanelmenu.mod',
        localstorage: 'lib/backbone.localStorage-min',
        select2: 'lib/select2.min',
        underscore: 'lib/underscore-min'
    },

    shim: {
        backbone: {
            deps: ['underscore', 'jquery'],
            exports: 'Backbone'
        },
        Handlebars: {
            exports: 'Handlebars'
        },
        hbs: {
            deps: ['Handlebars']
        },
        jquery: {
            exports: '$'
        },
        jqueryhammer: {
            deps: ['jquery', 'hammer']
        },
        jqueryjpanelmenu: {
            deps: ['jquery']
        },
        select2: {
            deps: ['jquery'],
            exports: 'Select2'
        },
        underscore: {
            exports: '_'
        }
    },

    // Config for Handlebars plugin.
    hbs: {
        disableI18n: true
    }

});

require([
    'jquery',
    'jqueryhammer',
    'jqueryjpanelmenu',
    'backbone',
    'localstorage',
    'Handlebars',
    'app',
    'router'
], function($, Hammer, jQueryJPanelMenu, Backbone, localstorage, Handlebars, app, Router) {

   ...

});

My build-config.js looks like this:

({
    baseUrl: 'js',
    name: 'main',
    mainConfigFile: 'js/main.js',
    out: 'main-built.js'
})

My directory structure looks like this:

./build-config.js
./js
./js/app.js
./js/collections
./js/collections/books.js
./js/collections/highlights.js
./js/collections/questions.js
./js/collections/users.js
./js/data
./js/data/tags.js
./js/lib
./js/lib/backbone-min.js
./js/lib/backbone.localStorage-min.js
./js/lib/bootstrap.min.js
./js/lib/hammer.min.js
./js/lib/handlebars.js
./js/lib/hbs
./js/lib/hbs/i18nprecompile.js
./js/lib/hbs/json2.js
./js/lib/hbs/underscore.js
./js/lib/hbs.js
./js/lib/jquery-1.9.1.min.js
./js/lib/jquery.colorbox.js
./js/lib/jquery.hammer.js
./js/lib/jquery.jpanelmenu.mod.js
./js/lib/require.js
./js/lib/select2.min.js
./js/lib/underscore-min.js
./js/main.js
./js/models
./js/models/book.js
./js/models/chapter.js
./js/models/highlight.js
./js/models/mainModel.js
./js/models/question.js
./js/models/user.js
./js/router.js
./js/template
./js/template/courseContent
./js/template/courseContent/inlineQuestion.hbs
./js/template/courseContent/menu.hbs
./js/template/courseContent/selectionMenu.hbs
./js/template/helpers
./js/template/helpers/debug.js
./js/template/helpers/equals.js
./js/template/helpers/truncate.js
./js/template/questionAndAnswer
./js/template/questionAndAnswer/comment.hbs
./js/template/questionAndAnswer/question.hbs
./js/template/questionAndAnswer/questionThread.hbs
./js/template/toolbars
./js/template/toolbars/courseContent.hbs
./js/template/toolbars/general.hbs
./js/template/toolbars/popupPanels.hbs
./js/template/toolbars/question.hbs
./js/template/toolbars/userProfile.hbs
./js/views
./js/views/courseContent
./js/views/courseContent/bookView.js
./js/views/courseContent/highlightView.js
./js/views/courseContent/inlineQuestionView.js
./js/views/courseContent/menuView.js
./js/views/courseContent/selectionMenuView.js
./js/views/courseContentPageView.js
./js/views/courseHomePageView.js
./js/views/questionAndAnswer
./js/views/questionAndAnswer/questionThreadView.js
./js/views/questionPageView.js
./js/views/studentHomePageView.js
./js/views/toolbarView.js

The top of toolbarView looks like this:

define([
    'jquery',
    'underscore',
    'backbone',
    'app',
    'Handlebars',
    'hbs!template/toolbars/courseContent',
    'hbs!template/toolbars/general',
    'hbs!template/toolbars/question'
], function($, _, Backbone, app, Handlebars, CourseContentToolbar, GeneralToolbar, QuestionToolbar) {

I'm using require.js v2.1.5, handlebars v1.0.0-rc.3, hbs v0.4.0 and node v0.10.0.

Anyone know what could be wrong? Thanks in advance!

SlexAxton / require-handlebars-plugin

r.js optimizer build fails with 'Handlebars is not defined' #99