Per bug 22884, using "localhost" probably won't work on Windows. However, it's not...

diff --git a/includes/installer/Installer.i18n.php b/includes/installer/Installer.i18n.php
index 241f609..75d4ba8 100644 (file)
--- a/includes/installer/Installer.i18n.php
+++ b/includes/installer/Installer.i18n.php
@@ -172,7 +172,9 @@ Although MediaWiki checks all uploaded files for security threats, it is highly
        'config-db-host'                  => 'Database host:',
        'config-db-host-help'             => 'If your database server is on different server, enter the host name or IP address here.
 
-If you are using shared web hosting, your hosting provider should give you the correct host name in their documentation.',
+If you are using shared web hosting, your hosting provider should give you the correct host name in their documentation.
+
+If you are installing on a Windows server and using MySQL, using "localhost" may not work for the server name. If it does not, try "127.0.0.1" for the local IP address',
        'config-db-wiki-settings'         => 'Identify this wiki',
        'config-db-name'                  => 'Database name:',
        'config-db-name-help'             => 'Choose a name that identifies your wiki.