JBOSS5下部署struts2.1.8 项目报错，跪求解决方法！
建了一个最简单的struts2.1.8的项目，部署到tomcat6、JBOSS4.0上都没有问题，可是一部署到JBOSS5上就报下面的错误：
14:19:21,523 ERROR [Dispatcher] Dispatcher initialization failedUnable to load configuration. - bean - vfszip:/D:/server/jboss-5.1.0.GA/server/default/lib/struts2-core-2.1.8.1.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:374) at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:418) at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:69) at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:51) at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:234) at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:332) at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:90) at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3783) at org.apache.catalina.core.StandardContext.start(StandardContext.java:4413) at org.jboss.web.tomcat.service.deployers.TomcatDeployment.performDeployInternal(TomcatDeployment.java:310) at org.jboss.web.tomcat.service.deployers.TomcatDeployment.performDeploy(TomcatDeployment.java:142) at org.jboss.web.deployers.AbstractWarDeployment.start(AbstractWarDeployment.java:461) at org.jboss.web.deployers.WebModule.startModule(WebModule.java:118) at org.jboss.web.deployers.WebModule.start(WebModule.java:97) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:157) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:96) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:668) at org.jboss.system.microcontainer.ServiceProxy.invoke(ServiceProxy.java:206) at $Proxy38.start(Unknown Source) at org.jboss.system.microcontainer.StartStopLifecycleAction.installAction(StartStopLifecycleAction.java:42) at org.jboss.system.microcontainer.StartStopLifecycleAction.installAction(StartStopLifecycleAction.java:37) at org.jboss.dependency.plugins.action.SimpleControllerContextAction.simpleInstallAction(SimpleControllerContextAction.java:62) at org.jboss.dependency.plugins.action.AccessControllerContextAction.install(AccessControllerContextAction.java:71) at org.jboss.dependency.plugins.AbstractControllerContextActions.install(AbstractControllerContextActions.java:51) at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:348) at org.jboss.system.microcontainer.ServiceControllerContext.install(ServiceControllerContext.java:286) at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:1631) at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:934) at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1082) at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:984) at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:822) at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:553) at org.jboss.system.ServiceController.doChange(ServiceController.java:688) at org.jboss.system.ServiceController.start(ServiceController.java:460) at org.jboss.system.deployers.ServiceDeployer.start(ServiceDeployer.java:163) at org.jboss.system.deployers.ServiceDeployer.deploy(ServiceDeployer.java:99) at org.jboss.system.deployers.ServiceDeployer.deploy(ServiceDeployer.java:46) at org.jboss.deployers.spi.deployer.helpers.AbstractSimpleRealDeployer.internalDeploy(AbstractSimpleRealDeployer.java:62) at org.jboss.deployers.spi.deployer.helpers.AbstractRealDeployer.deploy(AbstractRealDeployer.java:50) at org.jboss.deployers.plugins.deployers.DeployerWrapper.deploy(DeployerWrapper.java:171) at org.jboss.deployers.plugins.deployers.DeployersImpl.doDeploy(DeployersImpl.java:1439) at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1157) at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1178) at org.jboss.deployers.plugins.deployers.DeployersImpl.install(DeployersImpl.java:1098) at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:348) at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:1631) at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:934) at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1082) at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:984) at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:822) at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:553) at org.jboss.deployers.plugins.deployers.DeployersImpl.process(DeployersImpl.java:781) at org.jboss.deployers.plugins.main.MainDeployerImpl.process(MainDeployerImpl.java:702) at org.jboss.system.server.profileservice.repository.MainDeployerAdapter.process(MainDeployerAdapter.java:117) at org.jboss.system.server.profileservice.repository.ProfileDeployAction.install(ProfileDeployAction.java:70) at org.jboss.system.server.profileservice.repository.AbstractProfileAction.install(AbstractProfileAction.java:53) at org.jboss.system.server.profileservice.repository.AbstractProfileService.install(AbstractProfileService.java:361) at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:348) at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:1631) at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:934) at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1082) at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:984) at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:822) at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:553) at org.jboss.system.server.profileservice.repository.AbstractProfileService.activateProfile(AbstractProfileService.java:306) at org.jboss.system.server.profileservice.ProfileServiceBootstrap.start(ProfileServiceBootstrap.java:271) at org.jboss.bootstrap.AbstractServerImpl.start(AbstractServerImpl.java:461) at org.jboss.Main.boot(Main.java:221) at org.jboss.Main$1.run(Main.java:556) at java.lang.Thread.run(Thread.java:619)Caused by: Unable to load bean: type: class:com.opensymphony.xwork2.ObjectFactory - bean - vfszip:/D:/server/jboss-5.1.0.GA/server/default/lib/struts2-core-2.1.8.1.jar/struts-default.xml:29:72 at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.register(XmlConfigurationProvider.java:221) at org.apache.struts2.config.StrutsXmlConfigurationProvider.register(StrutsXmlConfigurationProvider.java:101) at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:169) at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:55) ... 76 moreCaused by: Bean type class com.opensymphony.xwork2.ObjectFactory with the name xwork has already been loaded by bean - vfszip:/D:/server/jboss-5.1.0.GA/server/default/deploy/struts2.war/WEB-INF/lib/struts2-core-2.1.8.1.jar/struts-default.xml:29:72 - bean - vfszip:/D:/server/jboss-5.1.0.GA/server/default/lib/struts2-core-2.1.8.1.jar/struts-default.xml:29:72 at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.register(XmlConfigurationProvider.java:205) ... 79 more14:19:21,526 ERROR [[/struts2]] Exception starting filter struts2
