I upgraded my JBCS server to use EJB3 RC9, and as soon as I tried using webmail, I was getting all kinds of errors like:

javax.ejb.EJBException: java.lang.IllegalArgumentException: org.hibernat
e.hql.ast.QuerySyntaxException: JPA-QL compliance requires select clause

For those that are interested, it appears that EJB3 RC9 now enforces JPA-QL strict compliance by default. To get JBCS running, I followed the instructions at this link: http://www.hibernate.org/371.html#A4

Essentially, you need to add the following line to the Hibernate persistence.properties file (located at JBoss_HOME/server/default/deploy/ejb3.deployer/META-INF)

hibernate.query.jpaql_strict_compliance=false

Regards,
David