Tasks Assigned to Groups not found if creator or actor is null

Due to an error in a named query the call to org.jbpm.task.service.TaskServiceSession.getTasksAssignedAsPotentialOwner(final String userId, final List<String> groupIds, final String language) does not return results where the actor or creator is not set on a task.

There is a problem in the query called "TasksAssignedAsPotentialOwnerWithGroups".

See http://community.jboss.org/message/614902#614902 for a possible solution.