Hi all, I'm building a KnowledgeBase with KnowledgeAgent and a precompiled rule package. When the package contains a rule using temporal operators such "after" or "before" I get the exception listed at the end of this message. I'm using the latest version of drools 5 and my runtime configuration includes the following libraries: * drools-core - the rule engine itself. * drools-api * mvel2-2.0.10 * joda-time-1.6 the rule causing such a behaviour is: rule 'Test2' dialect 'mvel' when u1:UserType( firstName=="UserA" ) lie:UserEventType( event=="Login", user.id==u1.id) loe:UserEventType(event=="Logout", user.id==u1.id, this before lie) then Message msg = new Message();msg.setText("Test2 fired");driver.getMessages().add(msg); end java.lang.RuntimeException: KnowledgeAgent exception while trying to deserialize KnowledgeDefinitionsPackage at org.drools.agent.impl.KnowledgeAgentImpl.rebuildResources(KnowledgeAgentImpl.java:418) at org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet(KnowledgeAgentImpl.java:120) at org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet(KnowledgeAgentImpl.java:109) at info.vladimiro.tesi.peservice.KnowledgeBaseService.<init>(KnowledgeBaseService.java:94) at info.vladimiro.tesi.peservice.KnowledgeBaseService.getInstance(KnowledgeBaseService.java:65) at info.vladimiro.tesi.peservice.PEListener$KBTask.run(PEListener.java:35) at java.util.TimerThread.mainLoop(Timer.java:512) at java.util.TimerThread.run(Timer.java:462) Caused by: org.drools.RuntimeDroolsException: unable to determine operator for symbol [before] at org.drools.base.evaluators.Operator.determineOperator(Operator.java:71) at org.drools.base.evaluators.Operator.readResolve(Operator.java:106) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at java.io.ObjectStreamClass.invokeReadResolve(ObjectStreamClass.java:1033) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1728) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1305) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:348) at org.drools.base.BaseEvaluator.readExternal(BaseEvaluator.java:53) at ... Can someone help? Thanks in advance. Vladimiro Corsi