I had a similar problem and found it to be in the file jndi.properties under <all|default|mimimal>\conf.
I uncommented the line java.naming.provider.url=localhost and it seemed to solve my problem.
Maybe some body can explain why it's commented out
By commenting it out, it means the communication does not occur over the wire. This means everything is done within the JVM and therefore much faster - it also means better scalability.