Um projeto Struts + Hibernate dando erro no Tomcat

<action path="/LoginSubmit"
        type="pacote.LoginAction"
        name="usuario"
        scope="request"
        validate="true"
        input="/pages/login.jsp">
        <forward
            name="success"
            path="/pages/main.jsp"/></action>
  
    <action path="/Logoff"
        type="pacote.LogoffAction"
        name="usuario"
        scope="request"
        validate="false"
        input="/pages/teste.jsp"></action>

No arquivo LoginAction

package pacote;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpSession;

import org.apache.struts.action.Action;

import org.apache.struts.action.ActionError;

import org.apache.struts.action.ActionErrors;

import org.apache.struts.action.ActionForm;

import org.apache.struts.action.ActionForward;

import org.apache.struts.action.ActionMapping;

import pacote.Constantes;

import pacote.UsuarioDAO;

import pacote.Usuario;

public final class LoginAction extends Action

{

private Long id_usuario;

public ActionForward perform(ActionMapping mapping, 
							ActionForm form,
							javax.servlet.http.HttpServletRequest request,
							javax.servlet.http.HttpServletResponse response) 
							throws IOException,  ServletException {
								
	String login = ((Usuario)form).getLogin();
	String senha = ((Usuario)form).getSenha();
	
	Usuario user = UsuarioDAO.findByLogin(login);	
	boolean confirmado = checaSenha (user,senha);
	
	if(!confirmado)
	{
		//Usuário/senha não correspondem
		ActionErrors errors = new ActionErrors();
        errors.add(ActionErrors.GLOBAL_ERROR,
        new ActionError("error.login.denied"));
        saveErrors(request,errors);
        // return to input page
        return (new ActionForward(mapping.getInput()));
	}
	
    HttpSession httpSession = request.getSession();
    httpSession.setAttribute(Constantes.USER_KEY, user);
    httpSession.setAttribute("id_usuario", id_usuario);
    
    return (mapping.findForward(Constantes.SUCCESS));
}

public boolean checaSenha(Usuario user, String senha)
{
	if (user != null )
	{
		if (user.isFuncional() && user.getSenha().equals(senha))
		{
			id_usuario = user.getId_usuario();
			return true; // senha confere com o login
		}
	}
	return false; // senha não corresponde ao login ou login não existe
}