环境：
Win2000
Tomcat 4.12
JDK 1.4.0_02

Tomcat启动时,在console窗口出现如下错误信息，但是仍然可以运行servlet.

Tomcat-Standalone
Apache Tomcat/4.1.12
2002/10/29 9:28:16 org.apache.commons.digester.Digester error
致命的: Parse Error at line 47 column 11: The content of element type "web-app" must match "(icon?,display-name?,description?,distributable?,context-param*,servlet*,servlet-mapping*,session-config?,mime-mapping*,welcome-file-list?,error-page*,taglib*,resource-ref*,security-constraint*,login-config?,security-role*,env-entry*,ejb-ref*)".
org.xml.sax.SAXParseException: The content of element type "web-app" must match "(icon?,display-name?,description?,distributable?,context-param*,servlet*,servlet-mapping*,session-config?,mime-mapping*,welcome-file-list?,error-page*,taglib*,resource-ref*,security-constraint*,login-config?,security-role*,env-entry*,ejb-ref*)".
at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:232)
at org.apache.xerces.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:173)
at org.apache.xerces.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:362)
at org.apache.xerces.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:296)
at org.apache.xerces.impl.dtd.XMLDTDValidator.handleEndElement(XMLDTDValidator.java:1953)
at org.apache.xerces.impl.dtd.XMLDTDValidator.endElement(XMLDTDValidator.java:878)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.handleEndElement(XMLDocumentFragmentScannerImpl.java:1144)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:987)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(XMLDocumentFragmentScannerImpl.java:1445)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:333)
at org.apache.xerces.parsers.DTDConfiguration.parse(DTDConfiguration.java:524)
at org.apache.xerces.parsers.DTDConfiguration.parse(DTDConfiguration.java:580)
at org.apache.xerces.parsers.XMLParser.parse(XMLParser.java:152)
at org.apache.xerces.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1169)
at org.apache.commons.digester.Digester.parse(Digester.java:1495)
at org.apache.catalina.startup.ContextConfig.applicationConfig(ContextConfig.java:282)
at org.apache.catalina.startup.ContextConfig.start(ContextConfig.java:639)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:243)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:166)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:3493)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1188)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:738)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1188)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:347)
at org.apache.catalina.core.StandardService.start(StandardService.java:497)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:2189)
at org.apache.catalina.startup.Catalina.start(Catalina.java:510)
at org.apache.catalina.startup.Catalina.execute(Catalina.java:400)
at org.apache.catalina.startup.Catalina.process(Catalina.java:180)
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:324)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:203)
2002/10/29 9:28:23 org.apache.commons.digester.Digester error
致命的: Parse Error at line 47 column 11: The content of element type "web-app" must match "(icon?,display-name?,description?,distributable?,context-param*,servlet*,servlet-mapping*,session-config?,mime-mapping*,welcome-file-list?,error-page*,taglib*,resource-ref*,security-constraint*,login-config?,security-role*,env-entry*,ejb-ref*)".
org.xml.sax.SAXParseException: The content of element type "web-app" must match "(icon?,display-name?,description?,distributable?,context-param*,servlet*,servlet-mapping*,session-config?,mime-mapping*,welcome-file-list?,error-page*,taglib*,resource-ref*,security-constraint*,login-config?,security-role*,env-entry*,ejb-ref*)".
at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:232)
at org.apache.xerces.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:173)
at org.apache.xerces.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:362)
at org.apache.xerces.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:296)
at org.apache.xerces.impl.dtd.XMLDTDValidator.handleEndElement(XMLDTDValidator.java:1953)
at org.apache.xerces.impl.dtd.XMLDTDValidator.endElement(XMLDTDValidator.java:878)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.handleEndElement(XMLDocumentFragmentScannerImpl.java:1144)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:987)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(XMLDocumentFragmentScannerImpl.java:1445)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:333)
at org.apache.xerces.parsers.DTDConfiguration.parse(DTDConfiguration.java:524)
at org.apache.xerces.parsers.DTDConfiguration.parse(DTDConfiguration.java:580)
at org.apache.xerces.parsers.XMLParser.parse(XMLParser.java:152)
at org.apache.xerces.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1169)
at org.apache.commons.digester.Digester.parse(Digester.java:1495)
at org.apache.catalina.startup.ContextConfig.applicationConfig(ContextConfig.java:282)
at org.apache.catalina.startup.ContextConfig.start(ContextConfig.java:639)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:243)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:166)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:3493)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1188)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:738)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1188)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:347)
at org.apache.catalina.core.StandardService.start(StandardService.java:497)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:2189)
at org.apache.catalina.startup.Catalina.start(Catalina.java:510)
at org.apache.catalina.startup.Catalina.execute(Catalina.java:400)
at org.apache.catalina.startup.Catalina.process(Catalina.java:180)
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:324)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:203)

应该是按照顺序写吧

这一定是你在web.xml配制中,有配错的地方.
不一定[web-app]不匹配, 也可能是[web-app][/web-app]中的东西不匹配.
说不定[web-app][/web-app]的标点不对,这些都有可能.
你好好找一找吧

100%是web.xml问题。

你如果配置web.xml不能重复配置。

如，Tomcatconfweb.xml

    Tomcatwebapps***WEB-INFweb.xml

不能重复。

http://java.sun.com/dtd/web-app_2_3.dtd
web.xml是一个xml文件，上面是他的DTD定义文件，没有什么比这个文件说得更全了。

可能是你修改配置文件时修改错误了。