I'm using Hibernate 2.1x as an mbean with Jboss.  My configuration is 
exactly the same as described in the document (except the ds name and 
jndi name).    

My web app works fine for the first 8 or so hours and then I get the 
below exception whenever one of my business delegates tries to 
retrieve a dto/pojo from my dao: 

net.sf.hibernate.HibernateException: 
net.sf.hibernate.TransactionException: could not register 
synchronization with JTA TransactionManager 

Is hibernate leaking resource somewhere?