hbm2java help

I use hbm2java to generate my POJOs but I'm doing it based on the mapping defined in the hbm.xml file. What I wish to do actually is use jdbcconfiguration to reverse engineer from the database schema but I'm running into some problems.

When I try to run reverse engineering I get a "MappingException: Unable to configure overrides for Hibernate configuration". What exactly does this mean?

I still use Eclipse 3.0 so I am running the Hibernate toolset using ant.