使用grunt或节点服务器启动服务器时出错

我试图使用这里描述的平均堆栈:http://mean.io/

安装后,制作"grunt"时,出现错误:

debugger listening on port 5858
4 Jan 01:47:40 - [nodemon] reading ignore list
Express app started on port 3000

events.js:72
    throw er; // Unhandled 'error' event
          ^
Error: failed to connect to [localhost:27017]
    at null. (/mean/node_modules/mongoose/node_modules/mongodb/lib/mongodb/connection/server.js:540:74)
    at EventEmitter.emit (events.js:106:17)
    at null. (/mean/node_modules/mongoose/node_modules/mongodb/lib/mongodb/connection/connection_pool.js:140:15)
    at EventEmitter.emit (events.js:98:17)
    at Socket. (/mean/node_modules/mongoose/node_modules/mongodb/lib/mongodb/connection/connection.js:478:10)
    at Socket.EventEmitter.emit (events.js:95:17)
    at net.js:441:14
    at process._tickCallback (node.js:415:13)
4 Jan 01:47:40 - [nodemon] app crashed - waiting for file changes before starting...

我尝试了网站上指定的故障排除:更新Grunt,凉亭和清洁npm和凉亭缓存效果很好.但是更新npm也会出错:

npm ERR! error rolling back Error: Refusing to delete: /usr/local/bin/npm not in /usr/local/lib/node_modules/npm

这看起来像是自制软件和npm之间的冲突.但无论如何我安装了1.3.21版本.

我正在尝试时出现同样的错误node server.

你有什么想法让服务器工作吗？