I love slimstat, but think I stumbled over a bug today:
With line 4 of wp-slimstat-js.php you set the path to wp-config.phg using
$wp_root_folder = '../../..'; which may work fine in a standard wordpress installation, but not if you follow good practice for hardening wordpress, which also suggests to move wp-config.php outside your htdocs folder.
May I suggest you use lines 26 to 34 of wp-load.php which retrieves wp-config.php from the wordpress-folder, or – if missing – from the folder above.
Editing the plugin manually as your comment in wp-slimstat-js.php line 3/6 suggests is undesirable.
Is there any particular reason that you do direct mysql_connects instead of using the $wpdb object?
"Tanti Saluti", pixolin