I also have the userId problem. From the logs:
23:07:33,566 ERROR [stderr] (Thread-19) java.lang.IllegalArgumentException: org.hibernate.QueryParameterException: could not locate named parameter [userId]
23:07:33,567 ERROR [stderr] (Thread-19) at org.hibernate.ejb.QueryImpl.setParameter(QueryImpl.java:206)
23:07:33,567 ERROR [stderr] (Thread-19) at org.jbpm.task.service.TaskServiceSession.getTasksAssignedAsPotentialOwnerByStatusByGroup(TaskServiceSession.java:1011)
23:07:33,567 ERROR [stderr] (Thread-19) at org.jbpm.task.service.TaskServerHandler.messageReceived(TaskServerHandler.java:356)
23:07:33,567 ERROR [stderr] (Thread-19) at org.jbpm.task.service.hornetq.HornetQTaskServerHandler.messageReceived(HornetQTaskServerHandler.java:44)
23:07:33,567 ERROR [stderr] (Thread-19) at org.jbpm.task.service.hornetq.BaseHornetQTaskServer.run(BaseHornetQTaskServer.java:85)
23:07:33,567 ERROR [stderr] (Thread-19) at java.lang.Thread.run(Thread.java:662)
23:07:33,568 ERROR [stderr] (Thread-19) Caused by: org.hibernate.QueryParameterException: could not locate named parameter [userId]
23:07:33,568 ERROR [stderr] (Thread-19) at org.hibernate.engine.query.ParameterMetadata.getNamedParameterDescriptor(ParameterMetadata.java:99)
23:07:33,568 ERROR [stderr] (Thread-19) at org.hibernate.engine.query.ParameterMetadata.getNamedParameterExpectedType(ParameterMetadata.java:105)
23:07:33,568 ERROR [stderr] (Thread-19) at org.hibernate.impl.AbstractQueryImpl.determineType(AbstractQueryImpl.java:437)
23:07:33,568 ERROR [stderr] (Thread-19) at org.hibernate.impl.AbstractQueryImpl.setParameter(AbstractQueryImpl.java:407)
23:07:33,569 ERROR [stderr] (Thread-19) at org.hibernate.ejb.QueryImpl.setParameter(QueryImpl.java:201)
23:07:33,569 ERROR [stderr] (Thread-19) ... 5 more