启动tomcat错误

严重: End event threw exception 
java.lang.IllegalArgumentException: Can't convert argument: null 
  at org.apache.tomcat.util.IntrospectionUtils.convert(IntrospectionUtils.java:976) 
  at org.apache.tomcat.util.digester.CallMethodRule.end(CallMethodRule.java:523) 
  at org.apache.tomcat.util.digester.Rule.end(Rule.java:229) 
  at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:1058) 
  at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:633) 
  at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1241) 
  at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(XMLDocumentFragmentScannerImpl.java:1685) 
  at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:368) 
  at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:834) 
  at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764) 
  at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:148) 
  at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1242) 
  at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1562) 
  at org.apache.catalina.startup.ContextConfig.applicationWebConfig(ContextConfig.java:369) 
  at org.apache.catalina.startup.ContextConfig.start(ContextConfig.java:1062) 
  at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:261) 
  at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117) 
  at org.apache.catalina.core.StandardContext.start(StandardContext.java:4239) 
  at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045) 
  at org.apache.catalina.core.StandardHost.start(StandardHost.java:719) 
  at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045) 
  at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443) 
  at org.apache.catalina.core.StandardService.start(StandardService.java:516) 
  at org.apache.catalina.core.StandardServer.start(StandardServer.java:710) 
  at org.apache.catalina.startup.Catalina.start(Catalina.java:566) 
  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:585) 
  at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288) 
  at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413) 
2009-12-15 21:21:11 org.apache.catalina.startup.ContextConfig applicationWebConfig 
严重: Parse error in application web.xml file at jndi:/localhost/news/WEB-INF/web.xml 
java.lang.IllegalArgumentException: Can't convert argument: null 
  at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.java:2726) 
  at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.java:2752) 
  at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:1061) 
  at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:633) 
  at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1241) 
  at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(XMLDocumentFragmentScannerImpl.java:1685) 
  at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:368) 
  at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:834) 
  at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764) 
  at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:148) 
  at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1242) 
  at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1562) 
  at org.apache.catalina.startup.ContextConfig.applicationWebConfig(ContextConfig.java:369) 
  at org.apache.catalina.startup.ContextConfig.start(ContextConfig.java:1062) 
  at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:261) 
  at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117) 
  at org.apache.catalina.core.StandardContext.start(StandardContext.java:4239) 
  at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045) 
  at org.apache.catalina.core.StandardHost.start(StandardHost.java:719) 
  at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045) 
  at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443) 
  at org.apache.catalina.core.StandardService.start(StandardService.java:516) 
  at org.apache.catalina.core.StandardServer.start(StandardServer.java:710) 
  at org.apache.catalina.startup.Catalina.start(Catalina.java:566) 
  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:585) 
  at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288) 
  at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413) 
2009-12-15 21:21:11 org.apache.catalina.startup.ContextConfig applicationWebConfig 
严重: Occurred at line 10 column 18