module.js:340 throw err; ^ Error: Cannot find module './settings'

我的app.js里面有require('./settings')但是出现了上面的错误，这是为什么呢？以前没有出现这个问题。下边是我的代码，请赐教。。。 var path = require('path'); var app = express(); var crypto = require('crypto'); var MongoStore = require('connect-mongo')(express); var settings = require('./settings'); // all environments app.set('port', process.env.PORT || 3000); app.set('views', path.join(__dirname, '/views')); app.set('view engine', 'ejs');