Index: wp-admin/network.php
===================================================================
--- wp-admin/network.php	(revision 16800)
+++ wp-admin/network.php	(working copy)
@@ -335,11 +335,16 @@
 ?>
 		<h3><?php esc_html_e( 'Enabling the Network' ); ?></h3>
 		<p><?php _e( 'Complete the following steps to enable the features for creating a network of sites.' ); ?></p>
-		<div class="updated inline"><p><?php
-			if ( iis7_supports_permalinks() )
-				_e( '<strong>Caution:</strong> We recommend you back up your existing <code>wp-config.php</code> file.' );
+		<div class="updated inline"><p><?php                
+                        if($is_IIS)
+                            $permalinkfile  =  file_exists(ABSPATH . DIRECTORY_SEPARATOR . 'web.config') ? " and <code>web.config</code> files." : " file."; 
+                        else
+                            $permalinkfile  =  file_exists(ABSPATH . DIRECTORY_SEPARATOR . '.htaccess') ? " and <code>.htaccess</code> files." : " file."; 
+                        
+			if ( iis7_supports_permalinks() )                            
+                            _e( '<strong>Caution:</strong> We recommend you back up your existing <code>wp-config.php</code>' . $permalinkfile);                        
 			else
-				_e( '<strong>Caution:</strong> We recommend you back up your existing <code>wp-config.php</code> and <code>.htaccess</code> files.' );
+                            _e( '<strong>Caution:</strong> We recommend you back up your existing <code>wp-config.php</code>' . $permalinkfile );
 		?></p></div>
 <?php
 	}