I’m having the same problem. Just installed on a Windows/IIS system, and when I tried to access wordpress/index.php, I got the error
Fatal error: require_once() [function.require]: Failed opening required ‘./wp-blog-header.php’
I went into wordpress/index.php, and changed the reference from ‘./wp-blog-header.php’ to ‘wp-blog-header.php’, and that solved that problem.
But I get the same kind of error when I try to access wordpress/wp-admin/index.php
Fatal error: require_once() [function.require]: Failed opening required ‘../wp-load.php’ (include_path=’.;c:\PHP5′) in D:\Inetpub\xxxx\wordpress\wp-admin\admin.php on line 20
I think the relative file reference looks OK. If I’m in wordpress/wp-admin/admin.php, I think that the reference of ../wp-load.php should point to wordpress/wp-load.php, which is a valid non-zero-byte file. Any ideas? The code in wp-admin/admin.php is
if ( defined(‘ABSPATH’) )
require_once(ABSPATH . ‘wp-load.php’);
else
require_once(‘../wp-load.php’);
