JPA Não aceita "select from usuario.tabela"

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE resources PUBLIC "-//Sun Microsystems, Inc.//DTD Application Server 9.0 Resource Definitions //EN" "http://www.sun.com/software/appserver/dtds/sun-resources_1_3.dtd">
<resources>
    <jdbc-connection-pool allow-non-component-callers="false" associate-with-thread="false" connection-creation-retry-attempts="0" connection-creation-retry-interval-in-seconds="10" connection-leak-reclaim="false" connection-leak-timeout-in-seconds="0" connection-validation-method="auto-commit" datasource-classname="com.sybase.jdbc2.jdbc.SybDataSource" fail-all-connections="false" idle-timeout-in-seconds="300" is-connection-validation-required="false" is-isolation-level-guaranteed="true" lazy-connection-association="false" lazy-connection-enlistment="false" match-connections="false" max-connection-usage-count="0" max-pool-size="32" max-wait-time-in-millis="60000" name="sybase2_externoPool" non-transactional-connections="false" pool-resize-quantity="2" res-type="javax.sql.DataSource" statement-timeout-in-seconds="-1" steady-pool-size="8" validate-atmost-once-period-in-seconds="0" wrap-jdbc-objects="false">
        <property name="serverName" value="187.5.218.39"/>
        <property name="User" value="simples"/>
        <property name="portNumber" value="49152"/>
        <property name="Password" value="simples"/>
        <property name="URL" value="jdbc:sybase:Tds:187.5.218.39:49152?ServiceName=teste"/>
        <property name="driverClass" value="com.sybase.jdbc2.jdbc.SybDataSource"/>
    </jdbc-connection-pool>
    <jdbc-resource enabled="true" jndi-name="Teste" object-type="user" pool-name="sybase2_externoPool"/>
</resources>

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" 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_2_0.xsd">
  <persistence-unit name="servicosPU" transaction-type="JTA">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <jta-data-source>teste</jta-data-source>
    <class>modelo.Clientes</class>
    <exclude-unlisted-classes>true</exclude-unlisted-classes>
    <properties>
    </properties>
  </persistence-unit>
</persistence>

package dao;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

public class PersistenceUtil {

    private static EntityManagerFactory emf = null;

    private PersistenceUtil() {
    }

    public static EntityManager getEntityManager(){
        if(emf == null)
            emf = Persistence.createEntityManagerFactory("servicosPU");
        return emf.createEntityManager();
    }

    public static void close(EntityManager em){
        if (em != null)
            em.close();
    }

}

package dao;

import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;
import javax.persistence.TypedQuery;
import modelo.Clientes;

public class ClientesDAO {

    private static ClientesDAO instance = new ClientesDAO();

    public static ClientesDAO getInstance() {
        return instance;
    }

    private ClientesDAO() {
    }

    public List<Clientes> getAllClientes() {
        EntityManager em = PersistenceUtil.getEntityManager();
        EntityTransaction tx = em.getTransaction();
        List<Clientes> clientes = null;
        try {
            tx.begin();
            TypedQuery<Clientes> query = (TypedQuery<Clientes>) em.createNamedQuery("Clientes.findAll");
            clientes = query.getResultList();
            tx.commit();
        } catch (Exception e) {
            if (tx != null && tx.isActive()) {
                tx.rollback();
            }
            throw new RuntimeException(e);
        } finally {
            PersistenceUtil.close(em);
        }
        return clientes;
    }

}

....
    public List<Clientes> getClientes() {
        ClientesDAO dao = ClientesDAO.getInstance();
        clientes = dao.getAllclientes();
        return clientes;
    }
...