It looks like the JBPM task tables have changed a bit and the HelpDeskDemo no longer works under EAP + BRMS 6.5.0.Final-redhat-15.

23:49:46,853 INFO [org.hibernate.tool.hbm2ddl.SchemaUpdate] (ServerService Thread Pool – 73) HHH000232: Schema update complete
23:49:46,995 ERROR [org.hibernate.hql.internal.ast.ErrorCounter] (ServerService Thread Pool – 73) Unable to locate appropriate constructor on class [org.jbpm.services.task.query.TaskSummaryImpl]. Expected arguments are: long, java.lang.String, java.lang.String, org.kie.api.task.model.Status, int, java.lang.String, java.lang.String, java.util.Date, java.util.Date, java.util.Date, java.lang.String, long, long, java.lang.String, boolean
[cause=org.hibernate.PropertyNotFoundException: no appropriate constructor in class: org.jbpm.services.task.query.TaskSummaryImpl]
23:49:46,995 ERROR [org.hibernate.hql.internal.ast.ErrorCounter] (ServerService Thread Pool – 73) Unable to locate appropriate constructor on class [org.jbpm.services.task.query.TaskSummaryImpl]. Expected arguments are: long, java.lang.String, java.lang.String, org.kie.api.task.model.Status, int, java.lang.String, java.lang.String, java.util.Date, java.util.Date, java.util.Date, java.lang.String, long, long, java.lang.String, boolean
[cause=org.hibernate.PropertyNotFoundException: no appropriate constructor in class: org.jbpm.services.task.query.TaskSummaryImpl]: Unable to locate appropriate constructor on class [org.jbpm.services.task.query.TaskSummaryImpl]. Expected arguments are: long, java.lang.String, java.lang.String, org.kie.api.task.model.Status, int, java.lang.String, java.lang.String, java.util.Date, java.util.Date, java.util.Date, java.lang.String, long, long, java.lang.String, boolean
[cause=org.hibernate.PropertyNotFoundException: no appropriate constructor in class: org.jbpm.services.task.query.TaskSummaryImpl]
at org.hibernate.hql.internal.ast.tree.ConstructorNode.resolveConstructor(ConstructorNode.java:188) [hibernate-core-4.2.22.Final-redhat-1.jar:4.2.22.Final-redhat-1]