problem with timestamp (jdbc)

hi!

ExecGroup-0:err:No class found for datetime. :-?

*this is the table running under postgresql 6.5.3
*+----------------------------------+----------------------------------+-------+

*| Field | Type |
Length|
*+----------------------------------+----------------------------------+-------+

*| cod_habitacion | int4 not null default nextval('"
| 4 |
*| cod_tipo_habitacion | int4 not null
| 4 |
*| numero | int4 not null
| 4 |
*| planta | int4 not null
| 4 |
*| observaciones | text
| var |
*| total_facturado | float4
| 4 |
*| noche_ocupada | int4
| 4 |
*| noche_libre | int4
| 4 |
*| noche_bloqueada | int4
| 4 |
*| ultima | datetime
| 8 |
*+----------------------------------+----------------------------------+-------+

* Indices: habitaciones_cod_tipo_habit_key
* habitaciones_pkey
*/

// here is sniped code

import com.codestudio.util.*;
import java.util.Vector;
import java.util.Date;
import java.sql.*;

public class Habitacion_BDImpl implements Habitacion_Int {

private final int NOCHE_LIBRE_POS=8;
private final int NOCHE_BLOQUEADA_POS=9;
private final int ULTIMA_POS=10;
private SQLManager manager = null;

public Habitacion[] Recoge_Habitacion() {

Habitacion habitacion = null;
Vector resp = new Vector();

try {
manager = SQLManager.getInstance();
}catch (PoolPropsException ex) {}

Connection con = manager.requestConnection();
PreparedStatement s = null;
ResultSet res = null;
try {
s = con.prepareStatement("SELECT * FROM
"+TABLA+" WHERE cod_habitacion=?");
s.setInt(1,cod.intValue());
res = s.executeQuery();
while (res.next()) {

habitacion.Set_Numero_Noches_Libre((Integer)res.getObject(NOCHE_LIBRE_POS));

habitacion.Set_Numero_Noches_Bloqueada((Integer)res.getObject(NOCHE_BLOQUEADA_POS));

/--------------->
habitacion.Set_Ultima_Estancia((Date)res.getObject(ULTIMA_POS));
}
} catch (SQLException sqle) { sqle.printStackTrace(); }
finally {
try {
s.clearParameters();
}catch (SQLException e) {e.printStackTrace();}
manager.closeResources(s, res);
manager.returnConnection(con);
}

Habitacion habitaciones[] = new Habitacion[resp.size()];
resp.copyInto(habitaciones);
return habitaciones;
}
}

// habitacion.Set_Ultima_Estancia expect a Date type ...
// There are any error at compiling time but when I try to run this
method this is the answer:

//ExecGroup-0:err:No class found for datetime. //
<----------- ?
// at postgresql.Connection.getObject(Connection.java, Compiled Code)
// at postgresql.jdbc2.ResultSet.getObject(ResultSet.java, Compiled
Code)
// at Habitacion_BDImpl.Recoge_Habitacion_Tipo(Habitacion_BDImpl.java,
Compiled Code)
// at ServerRMImpl.RecogeHab_Tipo(ServerRMImpl.java, Compiled Code)
// at java.lang.reflect.Method.invoke(Native Method)
// at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java,
Compiled Code)
// at sun.rmi.server.UnicastServerRef2.dispatch(UnicastServerRef2.java,
Compiled Code)
// at sun.rmi.transport.Transport$1.run(Transport.java, Compiled Code)
// at java.security.AccessController.doPrivileged(Native Method)
// at sun.rmi.transport.Transport.serviceCall(Transport.java, Compiled
Code)
// at
sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java,
Compiled Code)
// at
sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java,
Compiled Code)
// at java.lang.Thread.run(Thread.java, Compiled Code)

// What's wrong and how can I resolve it?