Carsten thank you for the heads up, to the best of my knowledge we didn’t change any of the Hibernate 2.1.7c libraries, but I will double check.
I think this may be a red herring, keeping in mind that the code you linked above is valid Hibernate 2.x code, if that is throwing an exception, then something else is likely wrong.
I wonder if you accidentally added Hibernate 3 libraries to your project?