Different display location for IE and FF

Hello, for the site I am working on, [url]www.roboticmagazine.com[/url] please look at the home page, to the blue menu buttons on the left side. they look normal for IE, but for FF they look on the top of the gray bar above. The correct look is like in IE.

Note that if you go to any other page, say, [url]www.roboticmagazine.com/toys.php[/url] the buttons look okay for FF as well. But for some reason, just for home page, they look over the top of the gray menu bar above. And I checked everything and didn’t notice anything that might cause the difference between the index page and other category pages. All category pages display menu bar at correct location in FF. What might be the reason? and how to correct?

And by the way, here is the css code:

.sidebuttons
{
position:absolute;
left:5px;
top:245px;
width:176px;
}

this is referred to in a specific file for side buttons and then it is first included in one file and then that file is included in all the files, to display side button on all pages.

and note that positioning is absolute…

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