//on page load call tb_init
$(document).ready(function(){   
    $("#okruhy li").not(".aktivni").hover(function(){
		$(this).css("background","#e4f9fa url(/img/bg-oblasti-l-on.gif) no-repeat");
	},
	function() {
		$(this).css("background","#ededed url(/img/bg-oblasti-l.gif) no-repeat");
	}
	);
});