[rules-users] NPE on retract

Hi, Using version 3.0.6 of jboss rules, while retracting an object, I get the following: java.lang.NullPointerException at org.drools.reteoo.beta.InstanceEqualConstrRightMemory.remove(Unknown Source) at org.drools.reteoo.BetaMemory.remove (Unknown Source) at org.drools.reteoo.NotNode.retractObject(Unknown Source) at org.drools.reteoo.ObjectSource.propagateRetractObject(Unknown Source) at org.drools.reteoo.RightInputAdapterNode.retractTuple (Unknown Source) at org.drools.reteoo.TupleSource.propagateRetractTuple(Unknown Source) at org.drools.reteoo.NotNode.retractTuple(Unknown Source) at org.drools.reteoo.TupleSource.propagateRetractTuple (Unknown Source) at org.drools.reteoo.JoinNode.retractObject(Unknown Source) at org.drools.reteoo.ObjectSource.propagateRetractObject(Unknown Source) at org.drools.reteoo.ObjectTypeNode.retractObject(Unknown Source) at org.drools.reteoo.Rete.retractObject(Unknown Source) at org.drools.reteoo.ReteooRuleBase.retractObject(Unknown Source) at org.drools.reteoo.ReteooWorkingMemory.doRetract(Unknown Source) at org.drools.common.AbstractWorkingMemory.retractObject(Unknown Source) at org.drools.common.AbstractWorkingMemory.retractObject(Unknown Source) at ascc.rules.AbstractRulesCoordinator.statusChanged( AbstractRulesCoordinator.java :354) at ascc.rules.AbstractRulesCoordinator$1.statusChanged( AbstractRulesCoordinator.java:111) at ascc.status.BaseStatusBoard.notifyChange(BaseStatusBoard.java:211) at ascc.status.BaseStatusBoard.notifyChange (BaseStatusBoard.java:191) at ascc.status.DefaultParkingStatusBoard.empty( DefaultParkingStatusBoard.java:318) at ascc.spotting.DefaultSpottingCoordinator.computeInitialSpot( DefaultSpottingCoordinator.java:578) at ascc.spotting.DefaultSpottingCoordinator.statusCreated( DefaultSpottingCoordinator.java:827) at ascc.status.BaseStatusBoard.notifyCreate(BaseStatusBoard.java:100) at ascc.status.BaseStatusBoard.notifyCreate (BaseStatusBoard.java:80) at ascc.status.DefaultAirPlanStatusBoard.missionAssignmentComplete( DefaultAirPlanStatusBoard.java:479) at ascc.missionassignment.Rule_6___Complete_mission_assignment_for_event_0.consequence(Rule_6___Complete_mission_assignment_for_event_0.java:36) at ascc.missionassignment.Rule_6___Complete_mission_assignment_for_event_0ConsequenceInvoker.evaluate(Rule_6___Complete_mission_assignment_for_event_0ConsequenceInvoker.java:24) ... 7 more Is there something I could be doing wrong? Is this a known bug? Thanks, -Chris