JavaMail and Gmail in Windows

Hello!

I made a java program to send and receive emails through Gmail SMTP server. It worked fine in Windows 7 but when I try to run the same program in Windows XP in a different machine, then the mail is not going. Either Messaging exception or SendMail exception comes. I have used JDK1.6 and NetBeans 5.5 to build this program.

Kindly let me know whether the issue is of operating system (in this case changes need to made accordingly) or some setting needs to be done in NetBeans, which somehow was taken by default in Windows 7.

The program is=

/*
* SendMail.java
*
* Created on 19 April, 2010, 10:14 AM
*
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
*/

package utility;

import java.io.Console;
import javax.mail.*;
import javax.mail.internet.*;
//import javax.activation.*;
import java.util.*;


/**
*
* @author Khushbu
* @version
*/
public class SendMail {

String username=null;
String password=null;

/** Creates a new instance of SendMail */
public SendMail() {
}

public void postMail( String recipients[ ], String subject, String message, String from, String pwd) throws MessagingException
{
boolean debug = false;

//Set the host smtp address
Properties props = new Properties();
//props.put("mail.smtp.host", "smtp.live.com");

String host="smtp.gmail.com";
props.put("mail.smtps.auth", "true");


// Authenticator a1= new PopupAuthenticator();


// create some properties and get the default Session
Session session = Session.getDefaultInstance(props, null);
session.setDebug(debug);

// create a message
Message msg = new MimeMessage(session);

// set the from and to address
//InternetAddress addressFrom = new InternetAddress(from);
//msg.setFrom(addressFrom);

InternetAddress[] addressTo = new InternetAddress[recipients.length];
for (int i = 0; i < recipients.length; i++)
{
addressTo[i] = new InternetAddress(recipients[i]);
}
msg.setRecipients(Message.RecipientType.TO, addressTo);

// Setting the Subject and Content Type
msg.setSubject(subject);
//msg.setContent(message, "text/plain");
msg.setText(message);
//Transport.send(msg);

username = from;
password = pwd;

Transport t = session.getTransport("smtps");
try {
t.connect(host, username, password);
//t.connect(host, username);
t.sendMessage(msg, msg.getAllRecipients());
} finally {
t.close();
}

}

}