Simple Jquery stopped working: addClass()

I am having a puzzling problem. A very simple piece of jquery just stopped working. It’s no longer adding the class; it doesn’t show in Firebug or the Chrome tools.

Here it is:

<script type=”text/javascript”>
jQuery(document).ready(function($){

$(‘#primary, #secondary’).addClass(‘equal_columns’);
$(‘.equal_columns’).equalHeights();
});
</script>

What I’ve tried:

Replace jQuery(document).ready(function($) with $(document).ready(function()

Put script in footer.

Put script before or after wp_head();

Any ideas?

Thanks.