Trap-effect bij menu in IE

/* THE MENU DIV WITH THE LI'S IN IT */
.menu {
	width: 93.15%;
	margin: 0em 5% 0% 4%;
	background-color: #99cc01;
	height: 1.8em;
	margin-bottom: 1%;
	text-align: right;
}

span.page {
	margin-right: 1em;
	padding-top: 0.5em;
	color: #fff;
}

/* NO THINGS IN FRONT OF THE MENU PARTS */
.menu li {
	list-style: none;
}

/* THE STYLE FROM THE MENU PARTS */
.menu li a{
	padding: 0.3em 2em;
	text-align: center;
	background-color: #99cc01;
	color: #FFFFFF;
	text-decoration: none;
	font-weight: bold;
	float: left;
	margin-right: 1px;
	border-right: 1px solid #fff;
}

/* THE MOUSE OVER FROM THE MENU PARTS */
.menu li a:hover{
	background-color: #ff9900;
}

<div class="menu">
    <li><a href="#">Kop1</a></li>
    <li><a href="#">Kop1</a></li>
    <li><a href="#">Kop1</a></li>
    <li><a href="#">Kop1</a></li>
    <li><a href="#">Kop1</a></li>
    <li><a href="#">Kop1</a></li>
    <span class="page">lala</span>
</div>