DoctrineMongoDBBundle getting a fatal error in Symfony2
Try fixing the bundle's version:
[DoctrineMongoDBBundle] git=http://github.com/symfony/DoctrineMongoDBBundle.git target=/bundles/Symfony/Bundle/DoctrineMongoDBBundle version=v2.0.0
And remember to always use bin/vendors install
— not bin/vendors update
. Unless you are developing Symfony itself, of course.