Problemas com JAVAMAIL

O galera to com esse problema aqui no javamail, ja coloquei a lib mail.jar e o restante dos .jar que vem no javamail na minha aplicacao dentro do web-inf e da essa seguinda excecao quando eu instancio a classe MimeMessage

MimeMessage msg = new MimeMessage(session);

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Servlet execution threw an exception

root cause

java.lang.NoClassDefFoundError: javax/activation/DataSource
util.Email.enviarEmail(Email.java:24)
actionMapping.formulario.InserirUsuarioEnderecoAction.execute(InserirUsuarioEnderecoAction.java:39)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:421)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:226)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:415)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

sera prq?

:cry:

No WEB-INF/lib vc colcou neh? Voce precisa colocar tambem o activation.jar

Rafael