急：struts2的问题

我部署项目的时候总是出现下面的错误：
nable to load bean: type: class:com.opensymphony.xwork2.ObjectFactory - bean - jar:file:/F:/工具/apache-tomcat-6.0.20/webapps/Struts2/WEB-INF/lib/struts2-core-2.1.8.1.jar!/struts-default.xml:29:72
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.register(XmlConfigurationProvider.java:208)
at org.apache.struts2.config.StrutsXmlConfigurationProvider.register(StrutsXmlConfigurationProvider.java:101)
at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reload(DefaultConfiguration.java:131)
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:52)
at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:395)
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:452)
at org.apache.struts2.dispatcher.FilterDispatcher.init(FilterDispatcher.java:201)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:275)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:397)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:108)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3800)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4450)
at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1173)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1271)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:296)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1337)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1601)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1590)
at java.lang.Thread.run(Unknown Source)
这是什么意思啊，请各位大虾帮帮忙！谢谢了！