严重: Exception starting filter struts2

tomcat启动信息如下：2010-11-23 21:03:19 org.apache.catalina.core.StandardContext filterStart
2010-11-23 21:03:19 org.apache.catalina.core.StandardContext filterStart
严重: Exception starting filter struts2
Unable to load configuration. - bean - jar:file:/D:/Program%20Files/Tomcat%206.0/webapps/Practice_Registration_Hibernate&Struts2/WEB-INF/lib/struts2-core-2.2.1.jar!/struts-default.xml:29:72
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:58)
at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:360)
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:403)
at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:69)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:48)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:295)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:422)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:115)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4001)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4651)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:546)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1041)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:964)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:502)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1277)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:321)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:785)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:445)
at org.apache.catalina.core.StandardService.start(StandardService.java:519)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:581)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
Caused by: Unable to load bean: type: class:com.opensymphony.xwork2.ObjectFactory - bean - jar:file:/D:/Program%20Files/Tomcat%206.0/webapps/Practice_Registration_Hibernate&Struts2/WEB-INF/lib/struts2-core-2.2.1.jar!/struts-default.xml:29:72
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.register(XmlConfigurationProvider.java:222)
at org.apache.struts2.config.StrutsXmlConfigurationProvider.register(StrutsXmlConfigurationProvider.java:101)
at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:165)
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:55)
... 31 more
Caused by: Bean type class com.opensymphony.xwork2.ObjectFactory with the name xwork has already been loaded by bean - jar:file:/D:/Program%20Files/Tomcat%206.0/webapps/Practice_Registration_Hibernate&Struts2/WEB-INF/lib/struts2-core-2.1.6.jar!/struts-default.xml:29:72 - bean - jar:file:/D:/Program%20Files/Tomcat%206.0/webapps/Practice_Registration_Hibernate&Struts2/WEB-INF/lib/struts2-core-2.2.1.jar!/struts-default.xml:29:72
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.register(XmlConfigurationProvider.java:206)
... 34 more
2010-11-23 21:03:19 org.apache.catalina.core.StandardContext start
严重: Error filterStart
2010-11-23 21:03:19 org.apache.catalina.core.StandardContext start
严重: Context [/Practice_Registration_Hibernate&Struts2] startup failed due to previous errors
log4j:ERROR LogMananger.repositorySelector was null likely due to error in class reloading, using NOPLoggerRepository.
郁闷的事，我把tomcat换了6.0.29，还是这样。照网上问谷老师的方法， 换了2个版本的sturts2 核心lib，2.2.21，2.1.6，2.0.14还是不行。是不是xwork包引起的？sturts2的filter我换成旧的filterDispathcher也不行，都快失去信心了。求教各为大侠！救火！