sonata-project/SonataNewsBundle — pull request #202 by mmf-amarcos (2014-05-30 11:46:30+00:00)
Title: Missing jmsserializer instance on appkerner. Update installation.rst

Installing the bundle I got
The service "sonata.classification.api.form.type.category" has a dependency on a non-existent service "jms_serializer.metadata_factory".

The library was present but not loaded on AppKernel.
Adding it solved the problem...