John, you may be right - some of those errors may be what're messing up Firefox for Darel, but WOW! Using the W3C tool will give just about any web developer nightmares.
For fun, I ran a number of websites through the site, and I still haven't found one which completely passes. Mine included.
Wish my development environment (I use Adobe's GoLive) was as picky. Judging by what I saw, others must not be any better.
BTW, I don't recommend GoLive. It came with a Photoshop bundle I bought years ago, so it just happens to be what I have readily available. The one section on my website that I let GoLive generate for me is the section the W3C tool barfed over the hardest! Mostly I hand code html and use the environment for editing, debugging, management and revision tracking.
Anybody who really knew web development would probably get a good belly-laugh out of the way I work.
Scott