Testing at http://d-theme.com/plutado_wide. The following line has an incomplete ul list, probably a missing menu.
<div id="nav"><ul class="menu">0</ul></div>

The following lines show a span element wrapped around elements that are not allowed in a span. Change the span to a div.

<span class="terms">
<div class="filed">Categories: </div><ul class="links inline"><li class="taxonomy_term_2 first last"><a href="/fixed" rel="tag" title="The theme is limited to a fixed width.">fixed</a></li></ul>
</span>

The following line contains an image without an alt attribute.
<img src="/sites/all/themes/plutado_wide/images/drupal.png" />