Import of a page based on event template doesn't work and raises an java.lang.ClassNotFoundException

My import file in attachement..

2009-01-13 17:48:03,843: ERROR [org.jahia.services.content.automation.Service] - Error during import of file /content/users/root/private/imports/importInto_ContentContainerList_88_20090113174803.zip
java.lang.ClassNotFoundException: No class defined for type [88]
at org.jahia.content.ObjectKey.getInstance(ObjectKey.java:164)
at org.jahia.services.content.automation.Service.importNode(Service.java:175)
at org.jahia.services.content.automation.Rule_Import_file_0.consequence(Unknown Source)
at org.jahia.services.content.automation.Rule_Import_file_0ConsequenceInvoker.evaluate(Unknown Source)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:550)
at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:514)
at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:462)
at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:434)
at org.drools.reteoo.ReteooStatelessSession.execute(ReteooStatelessSession.java:162)
at org.jahia.services.content.automation.RulesListener.onEvent(RulesListener.java:304)
at org.apache.jackrabbit.core.observation.EventConsumer.consumeEvents(EventConsumer.java:244)
at org.apache.jackrabbit.core.observation.ObservationDispatcher.run(ObservationDispatcher.java:145)
at java.lang.Thread.run(Thread.java:595)