Hi Abseve
Thank you for bringing this issue to our attention. To resolve the problem you can simply re download the template and install via your Extensions Manager.
Alternatively you can replace the following in your templates scripts.php (../templates/j51_letterpress/php/scripts.php)...
<!-- Hornav Responsive Menu -->
<script type="text/javascript" src="/<?php echo $this->baseurl ?>/templates/<?php echo $this->template ?>/js/responsive-nav/responsive-nav.js" charset="utf-8"></script>
<script type="text/javascript">
jQuery(function(){
jQuery('#hornav').slicknav();
});
</script>
With...
<?php if($responsive_sw == "1") : ?>
<!-- Hornav Responsive Menu -->
<script type="text/javascript" src="/<?php echo $this->baseurl ?>/templates/<?php echo $this->template ?>/js/responsive-nav/responsive-nav.js" charset="utf-8"></script>
<script type="text/javascript">
jQuery(function(){
jQuery('#hornav').slicknav();
});
</script>
<?php endif; ?>
CiarĂ¡n