Hi guys, I meet a problem, and need you guys ' help. I am very appreciative if anyone gives anyone suggestion. well, here is the problem. After configur and install the xwiki follwing the reference, I got exceptions when I access the xwiki web home. following is the exceptions ' stack info. ( xwiki-0.9.1252, jdk 5.0 tomcat 5.0) 2007-03-19 14:50:58 StandardWrapperValve[action]: Servlet.service() for servlet action threw exception com.xpn.xwiki.XWikiException: Error number 3 in 0: Could not initialize main XWiki context Wrapped Exception: Error number 3202 in 3: Exception while reading document XWiki.XWikiPreferences Wrapped Exception: Error number 7005 in 7: Error instanciating property class Wrapped Exception: null at com.xpn.xwiki.XWiki.getMainXWiki(XWiki.java:201) at com.xpn.xwiki.XWiki.getXWiki(XWiki.java:262) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:98) at org.apache.struts.action.RequestProcessor.processActionPerform( RequestProcessor.java:421) at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java :226) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164) at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:397) at javax.servlet.http.HttpServlet.service(HttpServlet.java:689) at javax.servlet.http.HttpServlet.service(HttpServlet.java:802) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter( ApplicationFilterChain.java:252) at org.apache.catalina.core.ApplicationFilterChain.doFilter( ApplicationFilterChain.java:173) at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter( SetCharacterEncodingFilter.java:127) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter( ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter( ApplicationFilterChain.java:173) at org.apache.catalina.core.StandardWrapperValve.invoke( StandardWrapperValve.java:214) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.StandardContextValve.invokeInternal( StandardContextValve.java:198) at org.apache.catalina.core.StandardContextValve.invoke( StandardContextValve.java:152) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java :137) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java :118) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:102) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.StandardEngineValve.invoke( StandardEngineValve.java:109) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929) at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java :799) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection (Http11Protocol.java:705) at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java :577) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run( ThreadPool.java:684) at java.lang.Thread.run(Thread.java:595) Wrapped Exception: com.xpn.xwiki.XWikiException: Error number 3202 in 3: Exception while reading document XWiki.XWikiPreferences Wrapped Exception: Error number 7005 in 7: Error instanciating property class Wrapped Exception: null at com.xpn.xwiki.store.XWikiHibernateStore.loadXWikiDoc( XWikiHibernateStore.java:429) at com.xpn.xwiki.store.XWikiCacheStore.loadXWikiDoc(XWikiCacheStore.java :143) at com.xpn.xwiki.XWiki.getDocument(XWiki.java:680) at com.xpn.xwiki.XWiki.getDocument(XWiki.java:715) at com.xpn.xwiki.XWiki.getPrefsClass(XWiki.java:1498) at com.xpn.xwiki.XWiki.initXWiki(XWiki.java:492) at com.xpn.xwiki.XWiki.<init>(XWiki.java:411) at com.xpn.xwiki.XWiki.getMainXWiki(XWiki.java:193) at com.xpn.xwiki.XWiki.getXWiki(XWiki.java:262) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:98) at org.apache.struts.action.RequestProcessor.processActionPerform( RequestProcessor.java:421) at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java :226) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164) at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:397) at javax.servlet.http.HttpServlet.service(HttpServlet.java:689) at javax.servlet.http.HttpServlet.service(HttpServlet.java:802) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter( ApplicationFilterChain.java:252) at org.apache.catalina.core.ApplicationFilterChain.doFilter( ApplicationFilterChain.java:173) at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter( SetCharacterEncodingFilter.java:127) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter( ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter( ApplicationFilterChain.java:173) at org.apache.catalina.core.StandardWrapperValve.invoke( StandardWrapperValve.java:214) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.StandardContextValve.invokeInternal( StandardContextValve.java:198) at org.apache.catalina.core.StandardContextValve.invoke( StandardContextValve.java:152) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java :137) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java :118) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:102) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.StandardEngineValve.invoke( StandardEngineValve.java:109) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929) at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java :799) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection (Http11Protocol.java:705) at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java :577) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run( ThreadPool.java:684) at java.lang.Thread.run(Thread.java:595) Wrapped Exception: com.xpn.xwiki.XWikiException: Error number 7005 in 7: Error instanciating property class Wrapped Exception: null at com.xpn.xwiki.objects.classes.BaseClass.fromXML(BaseClass.java:265) at com.xpn.xwiki.objects.classes.BaseClass.fromXML(BaseClass.java:286) at com.xpn.xwiki.store.XWikiHibernateStore.loadXWikiDoc( XWikiHibernateStore.java:354) at com.xpn.xwiki.store.XWikiCacheStore.loadXWikiDoc(XWikiCacheStore.java :143) at com.xpn.xwiki.XWiki.getDocument(XWiki.java:680) at com.xpn.xwiki.XWiki.getDocument(XWiki.java:715) at com.xpn.xwiki.XWiki.getPrefsClass(XWiki.java:1498) at com.xpn.xwiki.XWiki.initXWiki(XWiki.java:492) at com.xpn.xwiki.XWiki.<init>(XWiki.java:411) at com.xpn.xwiki.XWiki.getMainXWiki(XWiki.java:193) at com.xpn.xwiki.XWiki.getXWiki(XWiki.java:262) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:98) at org.apache.struts.action.RequestProcessor.processActionPerform( RequestProcessor.java:421) at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java :226) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164) at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:397) at javax.servlet.http.HttpServlet.service(HttpServlet.java:689) at javax.servlet.http.HttpServlet.service(HttpServlet.java:802) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter( ApplicationFilterChain.java:252) at org.apache.catalina.core.ApplicationFilterChain.doFilter( ApplicationFilterChain.java:173) at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter( SetCharacterEncodingFilter.java:127) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter( ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter( ApplicationFilterChain.java:173) at org.apache.catalina.core.StandardWrapperValve.invoke( StandardWrapperValve.java:214) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.StandardContextValve.invokeInternal( StandardContextValve.java:198) at org.apache.catalina.core.StandardContextValve.invoke( StandardContextValve.java:152) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java :137) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java :118) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:102) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.StandardEngineValve.invoke( StandardEngineValve.java:109) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929) at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java :799) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection (Http11Protocol.java:705) at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java :577) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run( ThreadPool.java:684) at java.lang.Thread.run(Thread.java:595) Wrapped Exception: java.lang.NullPointerException at com.xpn.xwiki.objects.classes.BaseClass.fromXML(BaseClass.java:256) at com.xpn.xwiki.objects.classes.BaseClass.fromXML(BaseClass.java:286) at com.xpn.xwiki.store.XWikiHibernateStore.loadXWikiDoc( XWikiHibernateStore.java:354) at com.xpn.xwiki.store.XWikiCacheStore.loadXWikiDoc(XWikiCacheStore.java :143) at com.xpn.xwiki.XWiki.getDocument(XWiki.java:680) at com.xpn.xwiki.XWiki.getDocument(XWiki.java:715) at com.xpn.xwiki.XWiki.getPrefsClass(XWiki.java:1498) at com.xpn.xwiki.XWiki.initXWiki(XWiki.java:492) at com.xpn.xwiki.XWiki.<init>(XWiki.java:411) at com.xpn.xwiki.XWiki.getMainXWiki(XWiki.java:193) at com.xpn.xwiki.XWiki.getXWiki(XWiki.java:262) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:98) at org.apache.struts.action.RequestProcessor.processActionPerform( RequestProcessor.java:421) at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java :226) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164) at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:397) at javax.servlet.http.HttpServlet.service(HttpServlet.java:689) at javax.servlet.http.HttpServlet.service(HttpServlet.java:802) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter( ApplicationFilterChain.java:252) at org.apache.catalina.core.ApplicationFilterChain.doFilter( ApplicationFilterChain.java:173) at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter( SetCharacterEncodingFilter.java:127) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter( ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter( ApplicationFilterChain.java:173) at org.apache.catalina.core.StandardWrapperValve.invoke( StandardWrapperValve.java:214) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.StandardContextValve.invokeInternal( StandardContextValve.java:198) at org.apache.catalina.core.StandardContextValve.invoke( StandardContextValve.java:152) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java :137) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java :118) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:102) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.StandardEngineValve.invoke( StandardEngineValve.java:109) at org.apache.catalina.core.StandardValveContext.invokeNext( StandardValveContext.java:104) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java :520) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929) at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java :799) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection (Http11Protocol.java:705) at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java :577) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run( ThreadPool.java:684) at java.lang.Thread.run(Thread.java:595) Thank you.