Bootstrap - Uncaught TypeError Cannot read property fn of undefined

Question

I am using jquery, backbonejs, underscorejs, and bootstrap for my project and I sometimes get this error in chrome.

Uncaught TypeError: Cannot read property 'fn' of undefined

My shim is like this in my main.js:

require.config({
paths: {
    jquery: 'libs/jquery/jquery',
    underscore: 'libs/underscore/underscore',
    backbone: 'libs/backbone/backbone',
    backboneeventbinder: 'libs/backbone.eventbinder.min',
    bootstrap: 'libs/bootstrap',
    jquerytablesorter: 'libs/tablesorter/jquery.tablesorter',
    tablesorter: 'libs/tablesorter/tables',
    ajaxupload: 'libs/ajax-upload',
    templates: '../templates'
},
shim: {
    'backbone': {
        deps: ['underscore', 'jquery'],
        exports: 'Backbone'
    },
    'underscore': {
        exports: '_'
    },
}
});
 require(['app', ], function(App) {
  App.initialize();
});

I inserted  .noConflict() for jquery, underscorejs and backbonejs.
My app.js:

// Filename: app.js
define(['jquery', 'underscore', 'backbone', 'backboneeventbinder', 'bootstrap', 'ajaxupload', 'router', // Request router.js
], function($, _, Backbone, Bootstrap, Backboneeventbinder, Ajaxupload, Router) {
    $.noConflict();
    _.noConflict();
    Backbone.noConflict();
    var initialize = function() {
            Router.initialize();
        };
    return {
        initialize: initialize
    };
});

Can someone help me with this?