Hi,
I'm way to much of a rookie to be giving php tips, but I also know how it feels, anxiously waiting to get the help needed so you can get your page working. So I will tell you what I did.
With your newpassword.php page open, look in the Server Behavior panel, and double click on the Update Record behavior. In the bottom of the Update Record window is "After updating, go to:".
Assuming you want your "success" message on the same page, you would place "newpassword.php?update=true" (without the quotes) in that "After updating, go to:" field.
Then in the code view window for the page, place this code (this is what I used, it differs slightly from Jasons tip)
<?php if(isset($_GET['update']) && ($_GET['update']) == "true"){ ?>
Your Profile has been updated
<?php } ?>
where ever you want the success message displayed. I placed mine at the top of the page at the end of the first line of text after a few " ". I also added a css style to make it stand out.
Dennis