struts2.1.6的配置问题

我从官方下的struts-2.1.6-all.zip  然后把里面的LIB的包全都导入了 但是出如下错误Unable to load configuration. - bean - jar:file:/D:/Tomcat%206.0/webapps/bar/WEB-INF/lib/struts2-convention-plugin-2.1.6.jar!/struts-plugin.xml:30:119
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.FilterDispatcher.init(FilterDispatcher.java:190)
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:3696)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4343)
at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1105)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1203)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:293)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
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)
Caused by: Unable to load bean: type:com.opensymphony.xwork2.UnknownHandler class:org.apache.struts2.convention.ConventionUnknownHandler - bean - jar:file:/D:/Tomcat%206.0/webapps/bar/WEB-INF/lib/struts2-convention-plugin-2.1.6.jar!/struts-plugin.xml:30:119
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)
... 17 more
Caused by: Bean type interface com.opensymphony.xwork2.UnknownHandler with the name default has already been loaded by bean - jar:file:/D:/Tomcat%206.0/webapps/bar/WEB-INF/lib/struts2-codebehind-plugin-2.1.6.jar!/struts-plugin.xml:29:122 - bean - jar:file:/D:/Tomcat%206.0/webapps/bar/WEB-INF/lib/struts2-convention-plugin-2.1.6.jar!/struts-plugin.xml:30:119
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.register(XmlConfigurationProvider.java:206)
... 20 more
求教