Index: wp-admin/install.php
===================================================================
--- wp-admin/install.php	(revision 4275)
+++ wp-admin/install.php	(working copy)
@@ -4,6 +4,8 @@
 	die("There doesn't seem to be a <code>wp-config.php</code> file. I need this before we can get started. Need more help? <a href='http://codex.wordpress.org/Installing_WordPress#Step_3:_Set_up_wp-config.php'>We got it</a>. You can <a href='setup-config.php'>create a <code>wp-config.php</code> file through a web interface</a>, but this doesn't work for all server setups. The safest way is to manually create the file.");
 
 require_once('../wp-config.php');
+if (file_exists('../wp-content/install.php')) 
+	require_once('../wp-content/install.php');
 require_once('./upgrade-functions.php');
 
 if (isset($_GET['step']))