G'Day mates, This time I will try to be more complete. So, I'm getting a error and decide to investigate. I'm using the least Xwiki version, 0.9.840, and this version is working fine with 3 user.Leaving another obstacles that I'm getting, every thing is running OK. This 3 users are admin users. Until this point, xWiki is working OK. But I'm tried to use another user, different of admin user. My problem starts here. When I navegate with this common user, in every page, show the same error. The error: com.xpn.xwiki.XWikiException: Error number 3213 in 3: Exception while deleting object XWiki.Mega Wrapped Exception: possible nonthreadsafe access to session at com.xpn.xwiki.store.XWikiHibernateStore.deleteXWikiCollection(XWikiHibernateStore.java:986) at com.xpn.xwiki.stats.impl.XWikiStatsServiceImpl.notify(XWikiStatsServiceImpl.java:209) at com.xpn.xwiki.notify.XWikiActionRule.verify(XWikiActionRule.java:51) at com.xpn.xwiki.notify.XWikiNotificationManager.verify(XWikiNotificationManager.java:93) at com.xpn.xwiki.web.ViewEditAction.execute(ViewEditAction.java:268) at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:421) at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:226) I tried to close some classes in Log4J, but I'm don't confortable with this masked errors. When I put the source in Eclipse to debug, I found where this error is "Blowing up". In com.xpn.xwiki.stats.impl.XWikiStatsServiceImpl.notify( )say it be necessary to delete the oldObject because the ID info have changed. Why do I need to delete this old object? This is occurring only in simple users. In admin mode this error don't happens. I'm looking for this error in xWiki mail list and Ludovic said that is a know problem and already fixed, but this answer was in december 2005 and the 0.9.840's version was build in september 2005. Are there anything that I can do to solve this problem in short-term? I'm thinking in remove the throw Exception. This short solution will be have big impact in xWiki? Cheers, Filipe Fumaux