Problem after updating from 3.2.1

We have a MS install that can’t seem to update from 3.2.1. The upgrade process works fine. The network update reports no errors. The site is configured for subdirectories. After updates all the content for the root site “/” works as expected. (www.example.com/about-us, etc.)

All sub-sites return a white screen. If I enable PHP error reporting via .htaccess I don’t get anything. If I turn on debug in wp-config I get “Deprecated: mysql_connect(): The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead in ~/public_html/wp-includes/wp-db.php on line 1142”

I have removed all plugins and themes.

Here’s the .htaccess:

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]

Here’s the wp-config (where I suspect my error is):

<?php
// ** MySQL settings - You can get this info from your web host ** //
// **there are valid db settings here... **//
/**#@+
 * Authentication Unique Keys and Salts.
// **there are valid keys and salts here **//
/**#@-*/

/**
 * WordPress Database Table prefix.*/
$table_prefix = 'stage_';

/**
 * WordPress Localized Language, defaults to English.
*/
define('WPLANG', '');

/**
 * For developers: WordPress debugging mode.
 */
define('WP_DEBUG', true);

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

define('ALTERNATE_WP_CRON', true);

define('ADMIN_COOKIE_PATH', '/');
define('COOKIE_DOMAIN', '');
define('COOKIEPATH', '');
define('SITECOOKIEPATH', '');

/* That's all, stop editing! Happy blogging. */

/** Absolute path to the WordPress directory. */
if ( !defined('ABSPATH') )
	define('ABSPATH', dirname(__FILE__) . '/');

/** Sets up WordPress vars and included files. */
require_once(ABSPATH . 'wp-settings.php');

Any suggestions would be greatly appreciated.