XHR错误（404 Not Found）加载http：// localhost：3000 / traceur

当我在代码中尝试使用Angular Material时，我遇到了以下错误 .

zone.js:101 GET http://localhost:3000/traceur 404 (Not Found)scheduleTask @ zone.js:101ZoneDelegate.scheduleTask @ zone.js:345Zone.scheduleMacroTask @ zone.js:282(anonymous function) @ zone.js:122send @ VM437:3fetchTextFromURL @ system.src.js:1156(anonymous function) @ system.src.js:1739ZoneAwarePromise @ zone.js:607(anonymous function) @ system.src.js:1738(anonymous function) @ system.src.js:2764(anonymous function) @ system.src.js:3338(anonymous function) @ system.src.js:3605(anonymous function) @ system.src.js:3990(anonymous function) @ system.src.js:4453(anonymous function) @ system.src.js:4705(anonymous function) @ system.src.js:408ZoneDelegate.invoke @ zone.js:332Zone.run @ zone.js:225(anonymous function) @ zone.js:591ZoneDelegate.invokeTask @ zone.js:365Zone.runTask @ zone.js:265drainMicroTaskQueue @ zone.js:497ZoneTask.invoke @ zone.js:437
    login:15 Error: Error: XHR error (404 Not Found) loading http://localhost:3000/traceur
    at XMLHttpRequest.wrapFn [as _onreadystatechange] (http://localhost:3000/node_modules/zone.js/dist/zone.js:794:30)
    at ZoneDelegate.invokeTask (http://localhost:3000/node_modules/zone.js/dist/zone.js:365:38)
    at Zone.runTask (http://localhost:3000/node_modules/zone.js/dist/zone.js:265:48)
    at XMLHttpRequest.ZoneTask.invoke (http://localhost:3000/node_modules/zone.js/dist/zone.js:433:34)
    Error loading http://localhost:3000/traceur
    Error loading http://localhost:3000/node_modules/@angular2-material/button/button.js as "@angular2-material/button" from http://localhost:3000/app/assets/js/app.module.js(anonymous function) @ login:15ZoneDelegate.invoke @ zone.js:332Zone.run @ zone.js:225(anonymous function) @ zone.js:591ZoneDelegate.invokeTask @ zone.js:365Zone.runTask @ zone.js:265drainMicroTaskQueue @ zone.js:497ZoneTask.invoke @ zone.js:437

以下是代码：
app.component.ts:

import { Component, ViewEncapsulation } from '@angular/core';
    import { MdButton } from '@angular2-material/button';
    @Component({
    selector: 'myApp',
    templateUrl: './app/app.html',
    styleUrls: ['./app/app.css'],
    encapsulation: ViewEncapsulation.None
    })
    export class AppComponent {
    }

app.module.ts:

import { NgModule } from '@angular/core';
    import { BrowserModule } from '@angular/platform-browser';
    import { FormsModule }   from '@angular/forms';
    import { HttpModule }    from '@angular/http';
    import { MdButtonModule } from '@angular2-material/button';
    import { routing, appRoutingProviders } from './app.routing';
    import { AppComponent } from './app.component';
    import { LoginModule } from './login/login.module';
    import { HomeModule } from './home/home.module';
    import { ItemsModule } from './items/items.module';
    import { MoviesModule } from './movies/movies.module';
    @NgModule({
    imports: [ BrowserModule, FormsModule, HttpModule, MdButtonModule, routing, LoginModule, HomeModule, ItemsModule, MoviesModule ],
    declarations: [ AppComponent ],
    providers: [ appRoutingProviders ],
    bootstrap: [ AppComponent ],
    })
    export class AppModule {}

app.routing.ts:

import { ModuleWithProviders } from '@angular/core';
    import { Routes, RouterModule } from '@angular/router';
    const appRoutes: Routes = [];
    export const appRoutingProviders: any[] = [];
    export const routing: ModuleWithProviders = RouterModule.forRoot(appRoutes);

main.ts:

import {platformBrowserDynamic} from '@angular/platform-browser-dynamic';
    import { AppModule } from './app.module';
    const platform = platformBrowserDynamic();
    platform.bootstrapModule(AppModule);

system.config.js:

/**
    * System configuration for Angular 2 samples
    * Adjust as necessary for your application needs.
    */
    (function (global) {
    System.config({
    paths: {
    // paths serve as alias
    'npm:': 'node_modules/'
    },
    // map tells the System loader where to look for things
    map: {
    // our app is within the app folder
    app: 'app',
    // angular bundles
    '@angular/core': 'npm:@angular/core/bundles/core.umd.js',
    '@angular/common': 'npm:@angular/common/bundles/common.umd.js',
    '@angular/compiler': 'npm:@angular/compiler/bundles/compiler.umd.js',
    '@angular/platform-browser': 'npm:@angular/platform-browser/bundles/platform-browser.umd.js',
    '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic.umd.js',
    '@angular/http': 'npm:@angular/http/bundles/http.umd.js',
    '@angular/router': 'npm:@angular/router/bundles/router.umd.js',
    '@angular/forms': 'npm:@angular/forms/bundles/forms.umd.js',
    '@angular2-material': 'npm:@angular2-material',
    // other libraries
    'rxjs':                       'npm:rxjs',
    'angular2-in-memory-web-api': 'npm:angular2-in-memory-web-api',
    },
    // packages tells the System loader how to load when no filename and/or no extension
    packages: {
    app: {
    main: './main.js',
    defaultExtension: 'js'
    },
    rxjs: {
    main: 'main.js',
    defaultExtension: 'js'
    },
    'angular2-in-memory-web-api': {
    main: './index.js',
    defaultExtension: 'js'
    },
    '@angular2-material/core': {
    main: 'core.js',
    defaultExtension: 'js'
    },     
    '@angular2-material/button': {
    main: 'button.js',
    defaultExtension: 'js'
    },      
    '@angular2-material/card': {
    main: 'card.js',
    defaultExtension: 'js'
    }
    }
    });
    })(this);

一旦我在"app.module.ts"的导入列表中添加 MdButtonModule ，我就开始收到错误 .