Failed validation, 4 errors
That is actually not too bad for a page of this complexity. I suspect it may have something to do with the theme, I validated this page while using Karyuus theme. Curiously the jigsaw validation timed out, but that could be because the page failed the first validation. The mysql and php ones are just promotional in nature.
Actually the css-validater seems to be off-line for some reason as I can't get to it even from w3c.org.
On further investigation the swf theme fails html validation in the same way so the problem is likely in the php script used to generate the page. I have a small amount of experience generating web pages with php and it can be frustrating getting it right.
