title: require statement in express js throws a error
body: <pre><code>var express = require('express')
  , signup = require('./routes/signup')
  ,login=require('./routes/login')  
  , http = require('http')
  , path = require('path')
  , cal=require('./routes/calculate')
  , db = require('./routes/db')
  
  , ejs = require('ejs')
  , moment = require('moment')
  , mysql = require('mysql');
  var pool  = require('pooling');
  
  var app = express();
  pool.initializepool(10);
  
  
  // all environments
   app.set('port', process.env.PORT || 3000);
   app.set('views', path.join(__dirname, 'views'));
   app.set('view engine', 'ejs');
  </code></pre>
  
  <p>the var pool does not throw an error when this is mentioned in app.js. But when the same line is mentioned in smoother node js file it throws a error saying  Cannot find module 'pooling'.
  this is my db.js file</p>
  
  <pre><code> var mysql = require('mysql');
   var pool  = require('pooling');
   exports.validate= function(callback,email,password)
  {
  var connection=pool.getConnection();
  var connection=connect();
    }
  </code></pre>
  
  <p>Please help</p>