Hi, i am learning to use EJB and i have some problems. I tried some examples but i can execute. Always i get the same error.
I am using Jboss 4.0.2 with Window XP.

My ejb-jar.xml is:

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE ejb-jar PUBLIC
"-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 2.0//EN"
"http://java.sun.com/dtd/ejb-jar_2_0.dtd">

<ejb-jar>
Calculo de Intereses
<display-name>Calculo</display-name>
<enterprise-beans>

<ejb-name>InteresesBean</ejb-name>
com.osmosislatina.ejb.intereses.InteresesHome
com.osmosislatina.ejb.intereses.Intereses
<ejb-class>com.osmosislatina.ejb.intereses.InteresesBean</ejb-class>
<session-type>Stateless</session-type>
<transaction-type>Bean</transaction-type>

</enterprise-beans>
</ejb-jar>

And my clases are:

**********************
package com.osmosislatina.ejb.intereses;

import javax.ejb.SessionBean;
import javax.ejb.SessionContext;

public class InteresesBean implements SessionBean {

public double calcularInteres(double capital, double tasa, double plazo) {

return capital * Math.pow(1+tasa, plazo) - capital;
}

public InteresesBean() {}
public void ejbCreate() {}
public void ejbRemove() {}
public void ejbPassivate() {}
public void ejbActivate() {}
public void setSessionContext(SessionContext sc) {}
}

**********************
package com.osmosislatina.ejb.intereses;

import javax.ejb.EJBObject;
import java.rmi.RemoteException;

public interface Intereses extends EJBObject {

public double calcularInteres(double capital, double tasa, double plazo)
throws RemoteException;

}
**********************
package com.osmosislatina.ejb.intereses;

import javax.ejb.EJBHome;
import javax.ejb.CreateException;
import java.rmi.RemoteException;

public interface InteresesHome extends EJBHome {

Intereses create() throws RemoteException, CreateException;

}
**********************
and the client is:


package com.osmosislatina.ejb.intereses;

import java.util.Properties;
import javax.rmi.PortableRemoteObject;
import javax.naming.*;

class ClienteIntereses
{
public static void main(String[] args)
{
Properties env = new Properties();
System.out.println("Inicio\n");
// Definir las propiededas y ubicación de búsqueda de Nombres JNDI.
env.setProperty("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory");
env.setProperty("java.naming.provider.url", "jnp://localhost:1099");
env.setProperty("java.naming.factory.url.pkgs", "org.jboss.naming.client");
env.setProperty("j2ee.clientName","ClienteIntereses");

//env.put(Context.INITIAL_CONTEXT_FACTORY, "org.openejb.client.LocalInitialContextFactory");

try
{
// Traer el Contexto de Nombre
InitialContext jndiContext = new InitialContext(env);
System.out.println("Contexto Disponible");

Object ref = jndiContext.lookup("InteresesBean");//THE PROBLEM IS HERE

InteresesHome home = (InteresesHome) PortableRemoteObject.narrow (ref, InteresesHome.class);

Intereses interes = home.create();

System.out.println("Interés de 10,000 Capital, a tasa 10%, bajo 2 plazos anuales:");
System.out.println("Fin");
}
catch(Exception e)
{
System.out.println("Error\n");
System.out.println(e.getMessage());
e.printStackTrace();
}
}
}

The error is in the line:
Object ref = jndiContext.lookup("InteresesBean");//THE PROBLEM IS HERE

I don't know what is the problem because i didn't write the program and another persons can execute without problems.
Can anybody help me, please?