bid/module/Members/view/members/error/not-found.phtml

<h3 class="headline">    
    <span>
        <?php echo $this->_('404 Error'); ?>
    </span>
</h3>

<h4>
    <?php echo $this->_('The page you are looking for could not be found.'); ?>
</h4>
<p>
    <?php echo $this->_('Try checking the URL for errors, then hit the refresh button on your browser.'); ?>
</p>