Java EE (Java Enterprise Edition) General Discussion

This is at the top of my JSP :

<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.com/jstl/xml" prefix="x" %>

I put the classes in the WEB-INF/lib

this works fine on my Tomcat 5.0.16, but gives the following error on my Tomcat 4 environment:

This absolute uri (http://java.sun.com/jstl/xml) cannot be resolved in either web.xml or the jar files deployed with this application

What should i do to get this tag library work on Tomcat 4? The TLD's are in /WEB-INF/

Thanks!