Inserção dum registo em MongoDB

<?php
  try
    {
      $m = new Mongo(); // connect
      $db = $m->selectDB("local");
    }
  catch ( MongoConnectionException $e )
    {
      echo '<p>Couldn\'t connect to mongodb, is the "mongo" process running?</p>';
      exit();
    }

  $db->users->insert( array( pnome => $_REQUEST['pnome'],
                         unome => $_REQUEST['unome'],
                         sexo => $_REQUEST['sexo'],
                         hacademicas => $_REQUEST['hacademicas']) );

  $collection = new MongoCollection($db, 'users');

  $cursor = $collection->find();

  foreach ($cursor as $doc)
  {
    echo "<pre>";
    var_dump($doc);
    echo "</pre>";
  }
?>