We had also some problems parsing hibernate cfg files in last time. The root of the cause was that the hibernate site was unreachable. After some googling and debugging org.hibernate.util.DTDEntityResolver class, I realized that there is also another way, how to specify the DTD URL:
<!DOCTYPE hibernate-configuration SYSTEM
"classpath://org/hibernate/hibernate-configuration-3.0.dtd">
This means that hibernate will load the DTD from classpath - it is usually included in hibernate jar in org/hibernate directory.
However, we use hibernate 3.5.6 - I don't hnow if this approach still works in the newer version - give it a try. The benefit of this is that you are completely independent on internet connection, proxies and so on.
