On symfony is a good idea to use the referer to costomize some messages, like this one below.

in template, you have to make a condition:

<?php if( $sf_request->getReferer() != '' ): ?>
  The page <?php echo $sf_request->getParameter('page'); ?> was changed.
<?php else: ?>
  The page <?php echo $sf_request->getParameter('page'); ?> not exists, check if you type correctly. 
<?php endif; ?>