Uncaught Error: Module "MQTT" not found

This is my code:

var server = "m14.cloudmqtt.com";
 var options = {
    client_id : "random",
    keep_alive: 60,
    port: 35577,
    clean_session: true,
    username: "ciugi**",
    password: "eYV1i*****",
    protocol_name: "MQTT",
    protocol_level: 4,
  };
  var mqtt = require("MQTT").create(server, options);
  mqtt.on('connected', function() {
    mqtt.subscribe("test");
  });
  mqtt.on('publish', function (pub) {
    console.log("topic: "+pub.topic);
    console.log("message: "+pub.message);
  });
var wifi = require("Wifi");
function onInit() {
   wifi.stopAP();
   wifi.connect("INGRIFAB", {password: "B73vFeX6se2"}, function(err) {
        if(err)console.log(err);else console.log("connected!");
        console.log(wifi.getIP().ip);
        });
}
var server = "m14.cloudmqtt.com";
 var options = {
    client_id : "random",
    keep_alive: 60,
    port: 35577,
    clean_session: true,
    username: "ciugi**",
    password: "eYV1i*****",
    protocol_name: "MQTT",
    protocol_level: 4,
  };
  var mqtt = require("MQTT").create(server, options);
  mqtt.on('connected', function() {
    mqtt.subscribe("test");
  });
  mqtt.on('publish', function (pub) {
    console.log("topic: "+pub.topic);
    console.log("message: "+pub.message);
  });
var wifi = require("Wifi");
function onInit() {
   wifi.stopAP();
   wifi.connect("INGRIFAB", {password: "B73vFeX6se2"}, function(err) {
        if(err)console.log(err);else console.log("connected!");
        console.log(wifi.getIP().ip);
        });
}
wifi.save();
save();