[CSS]Image RollOver

hi guys,
i have css script that supposed to do a rollover effect whenever the mouse over the image but apparently it only works in FF but not in IE, as far as I know IE can handle a:hover but not li:hover, etc., right? then where did i’ve done wrong?
the link is http://cg-animation.com/3d/illustrations/3d_illustration.html

this si the script:

<style type=“text/css” media=“screen”>
.rollover a{
filter:‘alpha(opacity=100)’;
opacity:1;
}
.rollover a:hover{
filter:‘alpha(opacity=50)’;
opacity:0.5;
}
</style>
<table id=“thumb_container” width=“220px” border=“0”>
<tr class=“rollover”>
<td><a href=“page1.html”><img src=“images1.jpg” alt="" /></a></td>
<td><a href=“page2.html”><img src=“images2.jpg” alt="" /></a></td>
</tr>
<tr class=“rollover”>
<td><a href=“page3.html”><img src=“images3.jpg” alt="" /></a></td>
<td><a href=“page4.html”><img src=“images4.jpg” alt="" /></a></td>
</tr>

</table>