JobExecutionException raised during importing prepackaed coporate demo

2009-04-09 09:51:16,156: INFO [org.quartz.core.JobRunShell] - Job ImportJob.BackgroundJob-cd59a523-9e26-4a0d-8dbd-11094bb0b571 threw a JobExecutionException:
org.quartz.JobExecutionException: javax.jcr.RepositoryException: this session has been closed [See nested exception: javax.jcr.RepositoryException: this session has been closed]
at org.jahia.services.scheduler.BackgroundJob.execute(BackgroundJob.java:176)
at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:525)
Caused by: javax.jcr.RepositoryException: this session has been closed
at org.apache.jackrabbit.core.SessionImpl.sanityCheck(SessionImpl.java:375)
at org.apache.jackrabbit.core.ItemImpl.sanityCheck(ItemImpl.java:137)
at org.apache.jackrabbit.core.NodeImpl.getParent(NodeImpl.java:2071)
at org.jahia.services.content.JCRNodeWrapperImpl.getParent(JCRNodeWrapperImpl.java:150)
at org.jahia.services.content.JCRNodeDecorator.getParent(JCRNodeDecorator.java:576)
at org.jahia.services.importexport.ImportJob.executeJahiaJob(ImportJob.java:173)
at org.jahia.services.scheduler.BackgroundJob.execute(BackgroundJob.java:164)
... 2 more