Hi everyone!

I am new to the forum and hope to find some help. I am not a developer, neither understand much about XHTML. I am trying to validate my wordpress website and I was able to correct some errors, but there's one I don't understand and I am unable to fix:

document type does not allow element "a" here; missing one of "object", "span", "bdo", "applet", "iframe", "tt", "i", "b", "u", "s", "strike", "big", "small", "font", "em", "strong", "dfn", "code", "q", "samp", "kbd", "var", "cite", "abbr", "acronym", "sub", "sup", "label", "ins", "del" start-tag.
I think this happens in this line:

<span class="number-of-comments"><a href="<?php the_permalink() ?>#comments" title="title"><?php comments_popup_link('Coment&aacute;rios', '1 Coment&aacute;rio!', '% Coment&aacute;rios!'); ?></a></span>
Any help would be great! Thanks!