java.sql.SQLException: No suitable driver

HI:
I'M TRYING TO CONNECT AN ECLIPSE 3.01 IDE RUNNING ON WINDOWS XP WITH A DB
POSTGRESQL VERSION 7.4.7. I USED THE FOLLOWINGS DRIVERS: PG.74.213/4/5/6.JDBC3.JAR
AND NO ONE WORKS.

THE MESSAGE WAS THE FOLLOWING:
Cargando clase
IWAV0055I Java Bean frenchconn.connpost started with the main method
java.sql.SQLException: No suitable driver
    at java.sql.DriverManager.getConnection(Unknown Source)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at frenchconn.connpost.agregarCliente(connpost.java:33)
    at frenchconn.connpost.main(connpost.java:69)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.eclipse.ve.internal.java.vce.launcher.remotevm.JavaBeansLauncher.main(JavaBeansLauncher.java:86)

AND THE CODE (MY CODE):

import java.sql.*;
import java.sql.DriverManager;
import java.sql.PreparedStatement;

//import samples.jdbc.JDBCTest;


/**
 * @author Benjamin
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public class connpost {

    static {
        System.out.println("Cargando clase");
      }

     public void agregarCliente(long idCliente,
               String nombre) {
             try {
               String url = "jdbc:postgres://172.16.100.110:5432/benjamin";
               Connection conn = null;
               conn = DriverManager.getConnection(url,"benjamin", "benja1");
              DriverManager.getDriver("org.postgresql.Driver");

               String sql =
                 "INSERT INTO Cliente " +
                 "(IdCliente, Nombre) " +
                 "VALUES (?,?)";

               PreparedStatement ps =
                 conn.prepareStatement(sql);

               ps.setLong(1, idCliente);
               ps.setString(2, nombre);

               ps.executeUpdate();

               ps.close();

               conn.close();

               System.out.println("Cliente insertado OK");
             }
             catch (Exception ex) {
               ex.printStackTrace();
             }
           }

    public static void main(String[] args) {

        try {
              // Cargo el driver JDBC de postgres
              Class.forName("org.postgresql.Driver");

              connpost conn = new connpost();
              //jdbcTest.agregarCliente(1, "Pepe");
              //jdbcTest.agregarCliente(2, "Juan");
              conn.agregarCliente(123,"pepe");

//              jdbcTest.transaccion();
            }
            catch (Exception ex) {
              ex.printStackTrace();
            }
    }
}


THANKS FOR EVERYTHING TO ANYONE

BENJAMIN