Database returned no natively generated id value [Closed]

I am using the latest release of MyEclipse 3.8.2 with Eclipse 3.0 on WinXP.
Using JVM 1.4.2_06 and Tomcat 5.0 with MySQL 4.1

First of all I was able to fix ( Session is closed ) error because of one of the posting here. Someone pointed out that the code that is created from Hibernate Wizard has a flaw. I had to add
if(session == null || session.isOpen() == false)
in currentSession() method.

well I have two new problems.

1) After I commit the codes to my CVS repository and downloaded them to my laptop which has the same software configuration, it give me JDBC Exception error: Cannot open connection. I doubled check hinerbate configuration files and .myhinernatedata file to make sure that they all have the correct information. Every files are the same. This is pretty strange. The only different is that I started the project with my office pc ( that is create DB exlpore profile ), add hibernate jar files and so on. I also checked my MySQL db and it has the same privileges user account and database as my office PC. I also created the same DB explore profile on my laptop. I even created new hibernate configuration file…It still doesn’t work…. Anyone know what is going on? May be someone already had the same experience before……I am newbie to hibernate.

2) Ok Back to my office PC……ok on my office PC, I can display the data fine. But when I try to add new data. it give me this error. What is that mean? I put all the debug statement in ContactService.java and found out that the error exception is happening in addContact( Contact data ) method. The method is implemented as follow. Should I add session.connection().commit(); and if the data doesn’t save, do session.connection().rollback();

Thanks in advance!
K~

public void addContact(Contact data)
{

Session session = null;

try
{
session = SessionFactory.currentSession();
session.save(data);
session.flush();
}
catch (HibernateException e)
{
System.err.println(“error from addContact….Hibernate Exception” + e.getMessage());
throw new RuntimeException(e);
}
/*
* Regardless of whether the above processing resulted in an Exception
* or proceeded normally, we want to close the Hibernate session. When
* closing the session, we must allow for the possibility of a Hibernate
* Exception.
*
*/
finally
{
if (session != null)
{
try
{

session.close();
}
catch (HibernateException e)
{
System.err.println(“session error from addContact..Hibernate Exception” + e.getMessage());
throw new RuntimeException(e);
}

}
}

}

javax.servlet.ServletException: net.sf.hibernate.HibernateException: The database returned no natively generated identity value
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:545)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:486)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

root cause

java.lang.RuntimeException: net.sf.hibernate.HibernateException: The database returned no natively generated identity value
org.rcsb.pdb.cma.hibernate.ContactService.addContact(ContactService.java:267)
org.rcsb.pdb.cma.action.AddContact.execute(AddContact.java:51)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)