I'd start with your css, you have a couple of errors in template.css which I suspect is causing the logo to not display. Have a look at the css validator results here
and sort out the parse errors at the top.
You're also missing a closing img tag here:
<a href="/"><img src="/templates/dogs_cats_v2/images/spacer.gif" width="1" height="1" border="0" id="logo" ></a>
which I doubt is related, but best sort that as well.