Absolutely positioned images in Chrome/Safari

My client's websit has a navigation bar in the form of a wide image banner. I'm using the HTML <area> tag and JavaScript to overlay navigation buttons (which are themselves images) whenever the user mouses over certain regions of the banner. The buttons are absolutely positioned over their respective <area>'s, and are hidden/shown based on the mouse position.

While I have it working on Chrome, I've noticed that the buttons are appearing in the wrong place on Safari. I've struggled to figure out what the issue is, but haven'开发者_JAVA技巧t been successful so far. Has anyone encountered a problem like this before?

Here's a link to the draft of the site: http://bit.ly/dLIh4k. Thanks!

not sure if this applies to you but there are known issues with absolute positioning if the parent uses relative positioning.