Rules & alerts not working [BRM.10.1071] JMS: Exception

Dear all/ support

Suddenly rules configured in Optimize for Process 8 are no more working properly. Alerts are no more received by email and following Exception are appearing in Analytic Engine logs :

(OPTIMIZE) [Analytic Engine v8.0.3.0.EventRuleJmsMessageAdapter.UnknownKey] 2011-03-29 23:23:00.645 MST ERROR: javax.jms.JMSException: [BRM.10.1071] JMS: Exception occurred while getting object from Object Message: “com.webmethods.optimize.event.common.MonitorDimension; local class incompatible: stream classdesc serialVersionUID = -228921369937176746, local class serialVersionUID = -7351938362221792433”
at com.webmethods.jms.impl.WmObjectMessageImpl.getObject(WmObjectMessageImpl.java:169)
at com.webmethods.optimize.rules.common.EventRuleJmsMessageAdapter.adaptJmsMessage(EventRuleJmsMessageAdapter.java:55)
at com.webmethods.optimize.service.external.router.JMSListener.onMessage(JMSListener.java:104)
at com.webmethods.optimize.service.external.comm.JMSCommunication$ReceiverThread.run(JMSCommunication.java:603)
(OPTIMIZE) [Analytic Engine v8.0.3.0.EventRuleJmsMessageAdapter.UnknownKey] 2011-03-29 23:23:00.645 MST ERROR: Exception encountered when processing JMS message: com.webmethods.jms.impl.WmObjectMessageImpl[
headers={
JMSCorrelationID=null
JMSDeliveryMode=Non-persistent
JMSDestination=jmsqueue:/rule_event@sharedState=true
JMSExpiration=0
JMSMessageID=ID:1294074-3-92-59378
JMSPriority=4
JMSRedelivered=false
JMSReplyTo=null
JMSTimestamp=3/29/11 11:23 PM
JMSType=null
}
properties={
JMSXDeliveryCount=1
message_source_attr=0x0A3805630000012F0519101D37631FA4
}
body={
[BRM.10.1071] JMS: Exception occurred while getting object from Object Message: “com.webmethods.optimize.event.common.MonitorDimension; local class incompatible: stream classdesc serialVersionUID = -228921369937176746, local class serialVersionUID = -7351938362221792433”
}
]

Any idea ?

Thanks,
Regards,
Djibril.