Wordpress multisite causing Error 101 (net::ERR_CONNECTION_RESET): Unknown error.

Question

We have just installed WordPress 3.0.1 and everything worked fine. However, as soon as we started to install the multisite functionality by following this tutorial, things started to go wrong. At the end of step 5, the tutorial has you update your wp-config.php file and .htaccess file. Once we made the reccommended changes to these files, uploaded them back to the server and tried to re-log in, no pages would serve up anymore. We now get the following error for ALL pages in the blog:

Error 101 (net::ERR_CONNECTION_RESET): Unknown error.

Any ideas? Here are the code changes we made (following the sub-folder setup):

wp-config.php

define( 'MULTISITE', true );
define( 'SUBDOMAIN_INSTALL', false );
$base = '/';
define( 'DOMAIN_CURRENT_SITE', 'oursite.com' );
define( 'PATH_CURRENT_SITE', '/' );
define( 'SITE_ID_CURRENT_SITE', 1 );
define( 'BLOG_ID_CURRENT_SITE', 1 );

.htaccces file (in wordpress root directory)

# BEGIN WordPress
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

# uploaded files
RewriteRule ^([_0-9a-zA-Z-]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]

# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]
# END WordPress