Вот мой пример - таки работает!
<!DOCTYPE html>
<html>
<head>
<script src="http://code.jquery.com/jquery-latest.js"></script>
<!--
<link rel="stylesheet" type="text/css" href="tmp.css" />
-->
<style type="text/css">
</style>
<script type="text/javascript">
$(document).ready(function(){
$('button').click(function() {
$('.CCheckBoxColumn').attr('checked',true);
});
});
</script>
</head>
<body>
<input class='CCheckBoxColumn' type="checkbox" />
<input class='CCheckBoxColumn' type="checkbox" />
<input class='CCheckBoxColumn' type="checkbox" />
<input class='CCheckBoxColumn' type="checkbox" />
<input class='CCheckBoxColumn' type="checkbox" />
<hr />
<button>Go</button>
</body>
</html>