Hello
Could you try replacing the following in your templates header.php (../templates/j51_nocturne/php/layouts/header.php - LINE30)...
<li class="social-flickr"<a href="/<?php echo $this->params->get('social_flickr'); ?>" target="_blank" title="Flickr">Flickr</a></li>
With..
<li class="social-flickr"><a href="/<?php echo $this->params->get('social_flickr'); ?>" target="_blank" title="Flickr">Flickr</a></li>
CiarĂ¡n