WordPress-MU -> Multisite WordPress -> Single WordPress instance

I once had an wordpress-mu instance, that was migrated to multisite wordpress once it was released with v3.0… but in time, apart from the main blog, the sub-blogs have become unused, and i want to (to simplyfy management) move everything to a single wordpress instance.

i’ve tried disabling just the multisite features, yet… it renders the blog unusable. what am i doing wrong, and what would be the best way to convert?

my current wp-config.php (secret sections removed):

<?php

define('VHOST', 'yes');
define('WP_ALLOW_MULTISITE', true);
define('WP_POST_REVISIONS', false);
define('WP_DEBUG_DISPLAY', false);
define('WP_DEBUG_LOG', 0);
define('WP_DEBUG', false);

$base = '/';

if( $base == 'BASE' )
	die( 'Problem in wp-config.php - $base is set to BASE when it should be the path like "/" or "/blogs/"! Please fix it!' );
$table_prefix  = 'wp_';

define( 'NOBLOGREDIRECT', 'http://www.ps3site.pl' );

define( "WP_USE_MULTIPLE_DB", false );

And the table layout in the db looks like this (after removing all the additional blogs):

| wp_1_commentmeta              |
| wp_1_comments                 |
| wp_1_links                    |
| wp_1_options                  |
| wp_1_postmeta                 |
| wp_1_posts                    |
| wp_1_term_relationships       |
| wp_1_term_taxonomy            |
| wp_1_terms                    |
| wp_blog_versions              |
| wp_blogs                      |
| wp_categories                 |
| wp_commentmeta                |
| wp_comments                   |
| wp_links                      |
| wp_options                    |
| wp_postmeta                   |
| wp_posts                      |
| wp_registration_log           |
| wp_signups                    |
| wp_site                       |
| wp_sitecategories             |
| wp_sitemeta                   |
| wp_term_relationships         |
| wp_term_taxonomy              |
| wp_terms                      |
| wp_usermeta                   |
| wp_users                      |

[moved to Multisite forum]