Heroku - Connetar with mongoDB addon mLab

I need to connect to the Mongo database using the mLO addOn. But I'm not able to insert or list, when running in local mode is working. I have the variable set:

Anyideawhatitmightbe?

Myapp.js

varexpress=require('express');varpath=require('path');varfavicon=require('serve-favicon');varlogger=require('morgan');varcookieParser=require('cookie-parser');varbodyParser=require('body-parser');varroutes=require('./routes/index');varusers=require('./routes/users');varmongoose=require('mongoose');varSchema=mongoose.Schema;varapp=express();//Herewefindanappropriatedatabasetoconnectto,defaultingto//localhostifwedon'tfindone.//'mongodb://heroku_28mj3757:[email protected]:31597/heroku_28mj3757';//MONGODB_URIvaruristring=process.env.MONGOLAB_URI||process.env.MONGOHQ_URL||'mongodb://localhost/HelloMongoose';////viewenginesetupapp.set('views',path.join(__dirname,'views'));app.set('viewengine','jade');//uncommentafterplacingyourfaviconin/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('/',routes);app.use('/users',users);//catch404andforwardtoerrorhandlerapp.use(function(req,res,next){varerr=newError('NotFound');err.status=404;next(err);});//errorhandlers//developmenterrorhandler//willprintstacktraceif(app.get('env')==='development'){app.use(function(err,req,res,next){res.status(err.status||500);res.render('error',{message:err.message,error:err});});}//productionerrorhandler//nostacktracesleakedtouserapp.use(function(err,req,res,next){res.status(err.status||500);res.render('error',{message:err.message,error:{}});});//Thehttpserverwilllistentoanappropriateport,ordefaultto//port5000.console.log("O valor da porta é:  " +process.env.PORT);
    console.log("O valor da porta é:  " +uristring);
    var theport = process.env.PORT || 5000;


        // Makes connection asynchronously.  Mongoose will queue up database
    // operations and release them when the connection is complete.
    mongoose.connect(uristring, function (err, res) {
      if (err) {
      console.log ('ERROR connecting to: ' + uristring + '. ' + err);
      } else {
      console.log ('Succeeded connected to: ' + uristring);
      }
    });

module.exports = app;

Routes where I insert / list;

   var userSchema = new mongoose.Schema({
      name: String,
      age:  Number
    });


var PUser = mongoose.model('PowerUsers', userSchema);



router.post('/insert', function(req, res, next) {
  //res.send({nome:"nome"}); 
  //console.("Ola mundo");
  //var Inscricaoo = mongoose.model('pessoas', inscricao);

  console.log("Route -  passou aqui ");

    // Creating one user.
    var johndoe = new PUser ({
      "name":"sara",
      "age": 25
    });



    // Saving it to the database.
    johndoe.save(function (err, result) {
        console.log("Errroooooo" + err);
    });

    res.send(johndoe);

});


router.get('/userlist', function(req, res, next) {
  //res.send({nome:"nome"}); 
  //console.("Ola mundo");
  //var Inscricaoo = mongoose.model('pessoas', inscricao);

  console.log("Route user list-  passou aqui ");
       // list all .
  PUser.find({}, function(err, users) {
    var userMap = {};

    users.forEach(function(user) {
      userMap[user._id] = user;
    });

    res.send(userMap);  
  });

});

heroku logs: