What is Wrong with filter and filter-mapping in My web.xml?

Question

First, thanks all for your attention.
I have checked the place where I should place <filter> and <filter-mapping> in web.xm. They should be after the <display-name>, before <servlet> and <servlet-mapping>.
However, as soon as I insert the <filter> and <filter-mapping> elements in my web.xml, all my struts-bean.tld, struts-html.tld, etc. in the web.xml cannot be found at the runtime.
Please help in identifying the problem. Thank you.
  <filter>
   <filter-name>trailFilter</filter-name>
   <filter-class>org.osjava.taglib.trail.OriginalRequestFilter</filter-class>
  </filter>
  <filter-mapping>
   <filter-name>trailFilter</filter-name>
   <url-pattern>*.do</url-pattern>
  </filter-mapping>and my web-xml is:
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
  PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
  "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
<web-app>
  <display-name>Struts Example Application</display-name>
  <!-- Action Servlet Configuration -->
  <servlet>
    <servlet-name>action</servlet-name>
    <servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
    <init-param>
      <param-name>config</param-name>
      <param-value>/WEB-INF/struts-config.xml, /WEB-INF/struts-config-registration.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <!-- Action Servlet Mapping -->
  <servlet-mapping>
    <servlet-name>action</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>
  <!-- The Welcome File List -->
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <!-- The default error page -->
  <error-page>
   <exception-type>java.lang.Exception</exception-type>
   <location>\Error.jsp</location>
  </error-page>
  <!-- Application Tag Library Descriptor -->
  <taglib>
    <taglib-uri>/tags/app</taglib-uri>
    <taglib-location>/WEB-INF/app.tld</taglib-location>
  </taglib>
  <!-- Struts Tag Library Descriptors -->
  <taglib>
    <taglib-uri>/tags/struts-bean</taglib-uri>
    <taglib-location>/WEB-INF/struts-bean.tld</taglib-location>
  </taglib>
  <taglib>
    <taglib-uri>/tags/struts-html</taglib-uri>
    <taglib-location>/WEB-INF/struts-html.tld</taglib-location>
  </taglib>
  <taglib>
    <taglib-uri>/tags/struts-logic</taglib-uri>
    <taglib-location>/WEB-INF/struts-logic.tld</taglib-location>
  </taglib>
  <taglib>
    <taglib-uri>/tags/struts-nested</taglib-uri>
    <taglib-location>/WEB-INF/struts-nested.tld</taglib-location>
  </taglib>
</web-app>

Answer 1

Multiple Post - http://forum.java.sun.com/thread.jspa?threadID=734506