Exception javax.persistence.PersistenceException: No Persistence provider for EntityManager

We've been working on this for days and we are stumped. This is supposed to be an easy tutortial using TopLink. We are trying to get this to work before we do our real web app. This is the following exception we get:

Exception in thread "main" javax.persistence.PersistenceException: No Persistence provider for EntityManager named pu1:
The following providers:
oracle.toplink.essentials.PersistenceProvider
oracle.toplink.essentials.ejb.cmp3.EntityManagerFactoryProvider
Returned null to createEntityManagerFactory.
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:154)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:83)
at client.Client.main(Client.java:45)
Java Result: 1

this happens after executing this line from our emf driver class:

emf = Persistence.createEntityManagerFactory("pu1");

I'm assuming the problem is in our persistence.xml file (which is in the correct folder (WEB-INF/classes/META-INF). Also netbeans generated the xml file for us which is:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" 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">
<persistence-unit name="JPAExamplePU" transaction-type="JTA">
<provider>oracle.toplink.essentials.PersistenceProvider</provider>
<jta-data-source>SomeDB</jta-data-source>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="toplink.ddl-generation" value="drop-and-create-tables"/>
</properties>
</persistence-unit>
</persistence>

We were also thinking it may be an adding a library issue or something along that line. Any help is much appreciated. Thanks