Mac OSX10.4.11 & Firefox3.6.19 - How do I make beeps stop on changing pages w/in a site?

Question

I'd been able to access the site (a part of the following site: http://www.govhs.org/) without beeps until yesterday. Unfortunately, it's a password-protected part of the site that I must deal with.
Is there ANY chance you can tell me why my laptop started to beep when I change pages within that site? If not, can you confirm that THEY must have changed something?

Answer 1

Oh, I didn't notice that it was another example of the most recurring question on Java GUI! Here's the idiom:
private void runButtonActionPerformed(java.awt.event.ActionEvent evt) {
  final List<ResultLine> res;
  resultArea.setText("");
  cancelButton.setEnabled(true);
  if (targetField.getText().isEmpty()){
    targetField.setText("localhost");
  Thread t = new Thread(new Runnable(){
    public void run(){
      String str = "";
      res = TR.traceroute
       (targetField.getText(), Settings.hops, Settings.waitTime);
      if (res == null){
        str = "Error";
      else{
        StringBuilder s = new StringBuilder();
        for (ResultLine r : res){
          s.append(r.toString());
          s.append("\n");
        str = s.toString();
      SwingUtilities.invokeLater(new Runnable(){
        public void run(){
          resultArea.setText(str);
          cancelButton.setEnabled(false);
  t.start();
}