the datasource jdbc/jbpm-ds is not defined. you can define a datasource in the container, or
just remove the <jta-data-source>jdbc/jbpm-ds</jta-data-source>, and then use the same configuration as org.jbpm.task, by configuring the database connection in the <properties> part of <persistence-unit name="org.jbpm.persistence.jpa"/>
Ted