http://www.achaea.com/ There's a splash screen with a meta refresh redirect. The nav menu uses onmousover behavior to make the menu pop, but the links are in html. Can you see anything immediately wrong about the site?
I had a quick peek, this might be the problem http://64.233.183.104/search?q=cache:http://www.achaea.com/main.php&hl=en&strip=1 this shows your site as the robot would see it. Does not look like the menu bars can be seen if you scroll over the links, it returns you to the same page. Easy work around is just put links to all your pages as a footer on each page.