Permalink / mod_rewrite issues

I’m having a bit of a problem getting my WordPress 2.1 install to recognize the date based permalinks.
The site in question is at http://stage.rapp.org/
You’ll notice the categorical archive links work fine. The monthly archives, however, do not work. I’ve read various messages here on the support forum about folks with internal server errors and such. I’m not having that problem. WordPress works fine, it just says “Sorry, no posts matched your criteria.”
Here is my .htaccess file:
RewriteEngine On
RewriteBase /
RewriteRule ^archives/(.*)/(feed|rdf|rss|rss2|atom)/?$ /wp-feed.php?category_name=$1&feed=$2 [QSA]
RewriteRule ^archives/?(.*) /index.php?category_name=$1 [QSA]
RewriteRule ^archives/author/(.*)/(feed|rdf|rss|rss2|atom)/?$ /wp-feed.php?author_name=$1&feed=$2 [QSA]
RewriteRule ^archives/author/?(.*) /index.php?author_name=$1 [QSA]
RewriteRule ^archives/([0-9]{4})?/?([0-9]{1,2})?/?([_0-9a-z-]+)?([0-9]+)?/?$ /index.php?year=$1&monthnum=$2&name=$3&page=$4 [QSA]
RewriteRule ^archives/([0-9]{4})/([0-9]{1,2})/([_0-9a-z-]+)?/(feed|rdf|rss|rss2|atom)/?$ /wp-feed.php?year=$1&monthnum=$2&name=$3&feed=$4 [QSA]
RewriteRule ^archives/([0-9]{4})/([0-9]{1,2})/([_0-9a-z-]+)?/trackback/?$ /wp-trackback.php?year=$1&monthnum=$2&name=$3 [QSA]
RewriteRule ^feed/?([_0-9a-z-]+)?/?$ /wp-feed.php?feed=$1 [QSA]
RewriteRule ^comments/feed/?([_0-9a-z-]+)?/?$ /wp-feed.php?feed=$1&withcomments=1 [QSA]
My template tag permalink is: /archives/%year%/%monthnum%/%postname%/
and my categories permalink is set to : /archives