帮我看看xml的错误

[dongqdonglin]

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sun-web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Application Server 8.1 Servlet 2.4//EN" "http://www.sun.com/software/appserver/dtds/sun-web-app_2_4-1.dtd">

<sun-web-app>
  <context-root>*****</context-root>
  <resource-ref>
    <res-ref-name>jdbc/DefaultDS</res-ref-name>
  </resource-ref>
  <cache enabled="true" max-entries="4096" timeout-in-seconds="30">
    <default-helper/>
  </cache>
  <class-loader delegate="true">
    <property name="delegate" value="true"/>
  </class-loader>
  <jsp-config/>
</sun-web-app>

这有什么错。。。。。**被我屏蔽了
<resource-ref>这地方老报错

[dongqdonglin]

急求

[dongqdonglin]

没人?