asp.net-mvc – 在VS2015中使用gulp在ASP.NET 4.5.2 MVC项目中编译LESS

我跟着this寻求帮助.
这是我到目前为止所做的：

添加了包含以下代码的package.json文件.

{
  "name": "package","version": "1.0.0","private": true,"devDependencies": {
    "gulp": "3.9.0","gulp-bower": "0.0.10","gulp-config": "0.3.0","gulp-less": "3.0.3","gulp-plumber": "1.0.1"
  }
}

在gulpfile.js中创建了一个Gulp任务

var gulp = require('gulp');
var less = require('gulp-less');
var path = require('path');
var plumber = require('gulp-plumber');
gulp.task('less',function () {
    return gulp.src('./Content/**/*.less')
    .pipe(plumber())
      .pipe(less({
          paths: [path.join(__dirname,'less','includes')]
      }))
      .pipe(gulp.dest('./content/'));
});

但后来我得到以下错误(在输出窗口中)：

我猜npm不要下载gulp.知道如何让这个工作吗？