I am trying out persistence and EJB 3, but I got this error when the jar is deployed:

10:06:55,887 ERROR [URLDeploymentScanner] Incomplete Deployment listing:

--- MBeans waiting for other MBeans ---
ObjectName: jboss.j2ee:jar=order.jar,name=ShoppingCartBean,service=EJB3
 State: NOTYETINSTALLED
 I Depend On:
 persistence.units:unitName=sample

--- MBEANS THAT ARE THE ROOT CAUSE OF THE PROBLEM ---
ObjectName: persistence.units:unitName=sample
 State: NOTYETINSTALLED
 Depends On Me:
 jboss.j2ee:jar=order.jar,name=ShoppingCartBean,service=EJB3

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
 version="1.0">
 <persistence-unit name="sample">
 <jta-data-source>java:/DefaultDS</jta-data-source>
 <properties>
 <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>
 <property name="hibernate.hbm2ddl.auto" value="create-drop"/>
 </properties>
 </persistence-unit>
</persistence>

package org.jboss.tutorial.entity.bean;

import javax.ejb.Remote;
import javax.ejb.Remove;
import javax.ejb.Stateful;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.PersistenceContext;


@Stateful
@Remote(ShoppingCart.class)
public class ShoppingCartBean implements ShoppingCart, java.io.Serializable
{
 @PersistenceContext(unitName="sample")
 private EntityManager manager;
 private Order order;

 public void buy(String product, int quantity, double price)
 {
 if (order == null) order = new Order();
 order.addPurchase(product, quantity, price);
 }

 public Order getOrder()
 {
 return order;
 }

 @Remove
 public void checkout()
 {
 manager.persist(order);
 }
}