CSS - Duplicate Div Id's

Hi,

In constructing my site www.brilliantprints.com.au. I used duplicate div ids for each line of the navigation menu.

It displays fine in IE but breaks in Firefox.

The menu is controlled by an individual style sheet.

chromestyle.css

I've been trying to fix it for almost a week now - but can't seem to come up with a solution that a) validates b) Isn't broken.

In terms of positioning and controlling the second div id (the lower navigation menu) does anyone have some quick suggestions.

I'm willing to go the hard yards if its a major problem - just run out of ideas.

Thanks

Dylan