help with validation!

hey everyone, im fairly new to wordpress and am working on a site zombiepoliticians.com. I cant find out what im doing wrong to get it validated.

if you can help im also need help on:

making the next and previous buttons into an image link

for some reason internet explorer doesnt like the site but firefox, safari, and chrome are fine.

getting the black border around the images to include the next previous links.

If you could help it would be deeply appreciated!

You can email me at joshpodcast at gmail dot com or twitter me @joshwhite