Browser Problem. All ok in FireFox but in IE it is centered. The same problem exists some time ago on the Groupee support board.
You use my koniro layout and if you dont make any changes the problem comes from the header or a custom island. Maybe you miss somewhere a close center statement.
Edit: found an opening center on your page but no closing center
<body onload="Text just to see where this shows up on the Forum :)" onclick="if(event.which!=3){clearMenus(event)}">
<a name="top"></a>
<center>
<img border="0" src="http://www.clubadventist.com/banner/clubadventistnew.gif" ></td>
