Error Not Found app.js - in node.js webscraper - node.js

Question

I just started learning node.js and following the webscraper example in this. After I typed "npm start" in the terminal and visited localhost:8081/scrape. I got this error message. I'm sure this file directory is correct.
Error: Not Found
at C:\Users\user\Desktop\Node.JS\webscraper\app.js:35:13
File tree:
here
Package.json
{
"name": "webscraper",
"version": "0.0.1",
"private": true,
"scripts": {
"start": "node ./bin/www"
},
"dependencies": {
"body-parser": "~1.17.1",
"cookie-parser": "~1.4.3",
"debug": "~2.6.3",
"express": "~4.15.2",
"jade": "~1.11.0",
"morgan": "~1.8.1",
"serve-favicon": "~2.4.2",
"request": "latest",
"cheerio": "latest"
}
}
After I deleted the following code generated by express in app.js, it works! May I ask why?
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
app.use('/', index);
app.use('/users', users);
// catch 404 and forward to error handler
app.use(function(req, res, next) {
var err = new Error('Not Found');
err.status = 404;
next(err);
});
// error handler
app.use(function(err, req, res, next) {
// set locals, only providing error in development
res.locals.message = err.message;
res.locals.error = req.app.get('env') === 'development' ? err : {};
// render the error page
res.status(err.status || 500);
res.render('error');
});