oracle forms 6i error problem(how to solve frm-40401 error)

Dear Sir,
  How are you, hope every one fine? I have one problem related to oracle forms6i.
 The complete scenario is: “I have a form name MCODE in which I placed some text fileds and combo box, and lov and I built this form manually. I create save button and behind this button I set a trigger to insert record into database. And another thing I add Alert code. For this I set code in PROGRAM UNITS (procedure) and I called only this procedure in save button. When I pressed save button, they tell me :”Are you sure you want to save record” I click OK to save record then another message open say “your record saved correctly”.
  Then another error alert open and say like that “ FRM-40401: NO CHANGES TO SAVE” BUT BASICALLY IT SAVES A RECORD IN DATABASE.
  TELL ME A REMEDY TO SOLVE SUCH PROBLEM.
  THANKS.
 AGAIN I USE ORACLE FORMS 6i.


SAVE BUTTON TRIGGER: WHEN BUTTON PRESSED AND ITS CODES IS GIVEN:
insert into mcode values(mcode_seq.nextval, :entry_form_block.cty_code,
:entry_form_block.categ_type, :entry_form_block.sub_name, :entry_form_block.address,
:entry_form_block.org, :entry_form_block.desg, :entry_form_block.email,
:entry_form_block.pager, :entry_form_block.entity, :entry_form_block.ph_type,
:entry_form_block.ahint, :entry_form_block.phone,:entry_form_block.date_form);

display_alert;

ACTUAL PROCEDURE IS DISPLAY_ALERT AND ITS CODES IS GIVEN:

PROCEDURE display_alert IS
      alert_button number;
BEGIN
  -- Call function to display alert and determine return value
  alert_button := show_alert('insert_alert');
 
  --determine  which button was pressed, and take appropriate action
  if alert_button = alert_button1 then
        commit;
        MESSAGE('Record successfully inserted.');
  else
        rollback;
        MESSAGE('Change roll back, no records updated.');
        end if;
END;
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