My b2evolution Version: Not Entered

I'm trying to get a list of posts between two and three years old, ordered by number of views. I have this code:

<h3 class="sideItemTitle">Old Favourites</h3>
<?php
	$search_date = date("Ymd", strtotime("-24 month"));
	$search_date2 = date("Ymd", strtotime("-36 month"));
	$TOPART = new ItemList($blog, array(), '', '', '', '', array(), '', 'DESC', 'views', 3,'','','','','','','','',$search_date2,$search_date);
	echo "<ul>";
	while ($TOPART_ITEM = $TOPART->get_item()) {
		echo "<li><a href=\"", $TOPART_ITEM->get_permanent_url();
		echo "\">", $TOPART_ITEM->title('','',false), "</a></li>";
	}
	echo "</ul>";
?>

I get no posts returned, even though I have blog posts going back to 2003. I assume I've messed up the arguments to the ItemList constructor somewhere, but simple munging like swapping the two dates around makes no difference to the output. Can anyone help?

Rob