Excluding categories from Recent Posts

[PogoFan]

I read through previous threads on this topic, but still need help. I want to exclude two categories (15 and 16) from the Recent Posts (renamed "Latest Headlines") that appears on my home page in the top sidebar.

I went into sidebar.php and edited the code this way:

<ul id="sidebarwidgeted">
	
	<?php if ( !function_exists('dynamic_sidebar') || !dynamic_sidebar('Sidebar Top') ) : ?>
	
	       <li id="recent-posts">
          <h2>Latest Headlines</h2>
          <ul>
             <?php $recent = new WP_Query("cat=-15,-16&showposts=5"); while($recent->have_posts()) : $recent->the_post();?>[*]<?php the_title(); ?>
             <?php endwhile; ?>[/list]          

		
	<?php endif; ?>
	
	[/list]

But nothing shows up on the home page at all for Latest Headlines that way. If I enable the Recent Posts widget, headlines from all categories show up, which I clearly don't want.

What am I doing wrong this time? :)