Having trouble with Sort By Date in sidebar…each month links to Category 5?

Hey there. This is my second wordpress theme but I’m converting somebody else’s HTML into a wp page. I’ve almost got everything sorted but I’m having an issue. In my sidebar.php, I have at the bottom

<!--Sort By Date-->

<h2 class="sidebar-title">Sort By Date</h2>
<ul class="archive-list">
<?php wp_get_archives( 'type=monthly' ); ?>
</ul>

and archive.php looks as follows

<?php get_header(); ?>

<div id="content"><!--Begin #content-->

<div id="main"><!--Begin #main-->
<div id="main2"><!--Begin #main2-->

		<?php if (have_posts()) : ?>

 			<?php $post = $posts[0]; // Hack. Set $post so that the_date() works. ?>

			<?php /* If this is a category archive */ if (is_category()) { ?>
				<h2>Archive for the ‘<?php single_cat_title(); ?>’ Category</h2>

			<?php /* If this is a tag archive */ } elseif( is_tag() ) { ?>
				<h2>Posts Tagged ‘<?php single_tag_title(); ?>’</h2>

			<?php /* If this is a daily archive */ } elseif (is_day()) { ?>
				<h2>Archive for <?php the_time('F jS, Y'); ?></h2>

			<?php /* If this is a monthly archive */ } elseif (is_month()) { ?>
				<h2>Archive for <?php the_time('F, Y'); ?></h2>

			<?php /* If this is a yearly archive */ } elseif (is_year()) { ?>
				<h2>Archive for <?php the_time('Y'); ?></h2>

			<?php /* If this is an author archive */ } elseif (is_author()) { ?>
				<h2>Author Archive</h2>

			<?php /* If this is a paged archive */ } elseif (isset($_GET['paged']) && !empty($_GET['paged'])) { ?>
				<h2>Blog Archives</h2>

			<?php } ?>

			<?php include (TEMPLATEPATH . '/inc/nav.php' ); ?>

			<?php while (have_posts()) : the_post(); ?>

				<div <?php post_class() ?>>

					<h2 id="post-<?php the_ID(); ?>"><a href="<?php the_permalink() ?>"><?php the_title(); ?></a></h2>

					<?php include (TEMPLATEPATH . '/inc/meta.php' ); ?>

					<div class="entry">
						<?php the_content(); ?>
					</div>

				</div>

			<?php endwhile; ?>

			<?php include (TEMPLATEPATH . '/inc/nav.php' ); ?>

	<?php else : ?>

		<h2>Nothing found</h2>

	<?php endif; ?>

<?php get_sidebar(); ?>

<?php get_footer(); ?>

My sidebar displays April 2011, which is the month I made some Test posts in. The hyperlink for april, however, is

https://localhost/soperfect_wp/?m=201104&cat=5

but the code for this link in the sidebar.php is

<!--Sort By Date-->

<h2 class="sidebar-title">Sort By Date</h2>
<ul class="archive-list">
<?php wp_get_archives( 'type=monthly' ); ?>
</ul>

So I don’t know where the page is getting the idea that I want it to generate a link to …/?m=201104&cat=5 instead of …/?m=201104

Any help would be sincerely appreciated.