Error Establishing a Database Connection

I know thist topic has been addressed many times, but never quite in the situation I’m having. My WP site (at http://www.dccsite.net/blog) is running fine — it displays properly to visitors and I can log in as admin. However, my main site (at http://www.dccsite.net) cannot extract posts. I am using a fairly standard piece of code:

<?php
    define('WP_USE_THEMES', false);
    require("blog/wp-blog-header.php");
?>
<div class="BlogExcerpts">
    <?php if (have_posts()) : while (have_posts()) : the_post(); ?>
    <h2><a href="<?php the_permalink(); ?>" rel="bookmark" title="Permanent
        link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></h2>
    <small><?php the_time('F jS, Y'); ?> by <?php the_author_posts_link(); ?></small>
    <p><?php the_excerpt(); ?></p>
    <?php endwhile; else: ?>
    <p><i>No news yet.</i></p>
    <?php endif; ?>
</div>

The point is to extract my blog post blurbs to my home page. This functionality worked fine up until a few weeks ago, at which time my entire WP install suffered a meltdown (all of my categories disappeared completely), which my provider (FatCow) tracked down and supposedly fixed. This particular brand of error (database connection) popped up after FatCow “fixed” the WP installation.

Any help is greatly appreciated.