Css rollover

Hello,
Long time i’ve not been here…
I’m near to the dead line and i’ve a little problem with my css rollover. It works in IE but not in Firefox. My css code is

#leftcolmenu ul{
	margin:0px 0px 0px 20px;
	padding:0;
	list-style-image: url(images/0187_green_star.png);
	font: 60% Verdana, Arial, Helvetica, sans-serif;
	color: #000000;
	list-style-position: outside;
	list-style-type: disc;
	text-decoration: none;
}

#leftcolmenu li a {
	display: block;
	list-style-image: url(images/0187_green_star.png);
	list-style-position: outside;
	text-decoration: none;
}
#leftcolmenu li a:hover, a:active {
	display: block;
	list-style-image: url(images/0188_pink_star.png);
	list-style-position: outside;
}

the html :

<ul>
		<li><a href="#URL_ARTICLE">#TITRE</a></li>
		</ul>

Can someone tell me what is wrong ?