Ошибка установки Doctrine-odm MongoDb в Symfony

У меня мало проблем с mongoDb и Symfony.
Я установил драйвер php 1.6.12 и хочу установить mongoDbBundle

добавить эти строки в мой composer.json

{
"require": {
"doctrine/mongodb-odm": "~1.0",
"doctrine/mongodb-odm-bundle": "~3.0"},

}

а потом

php composer.phar update doctrine/mongodb-odm doctrine/mongodb-odm-bundle

Но у меня есть эти ошибки

Your requirements could not be resolved to an installable set of packages.

Problem 1
- doctrine/mongodb-odm 1.0.0 requires doctrine/mongodb ~1.2 -> satisfiable by doctrine/mongodb[1.2.0, 1.2.1].
- doctrine/mongodb-odm 1.0.1 requires doctrine/mongodb ~1.2 -> satisfiable by doctrine/mongodb[1.2.0, 1.2.1].
- doctrine/mongodb-odm 1.0.2 requires doctrine/mongodb ~1.2 -> satisfiable by doctrine/mongodb[1.2.0, 1.2.1].
- doctrine/mongodb-odm 1.0.3 requires doctrine/mongodb ~1.2 -> satisfiable by doctrine/mongodb[1.2.0, 1.2.1].
- doctrine/mongodb-odm 1.0.4 requires doctrine/mongodb ~1.2 -> satisfiable by doctrine/mongodb[1.2.0, 1.2.1].
- doctrine/mongodb 1.2.1 requires ext-mongo ^1.2.12 -> the requested PHP extension mongo is missing from your system.
- doctrine/mongodb 1.2.0 requires ext-mongo ^1.2.12 -> the requested PHP extension mongo is missing from your system.
- Installation request for doctrine/mongodb-odm ~1.0 -> satisfiable by doctrine/mongodb-odm[1.0.0, 1.0.1, 1.0.2, 1.0.3, 1.0.4].