How to correct the error on my site?

Hi, I have this site and if you visit it with Firefox 4+, you would see the top menu items / links are wrongly positioned. If you visit it with Chrome or IE 7+, it’s all right.

It’s weird because before Firefox 4, it was all right. Seems I need to do something to adapt to the new algorithm of FF.

Any idea how I can do that?

Thanks!

I checked with Firefox 6/Win7, and everything looked okay. Maybe you can post some pictures of what’s happening?

Thanks for the heads-up. I’m attaching the screenshot here. error.png is what I see in FF 8, and correct.png is what I see in Chrome which is the correct style.

I upgraded to Firefox 7, which as far as I know is the current version, and it still looked good. Maybe this is a bug in a beta or nightly build of FF?