zzymurgy

Finally worked it out.

I had a very stupid line in my .htaccess file, as part of an effort to rid the web of nasty www prefixes.

The prefixes are still gone, but now so is the offending code and all is well.

This worked great for me. In case the link goes dead, let me reproduce it here. Upload this as force-upgrade.php and run it from a web browser:

`
<?php
/*
WordPress Force Upgrade Script
Copyright (C) 2006 Mark Jaquith

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/

function txfx_log($text) {
echo $text . ”;
}

switch ($_GET[‘step’]) :
case “1”:
require(‘wp-config.php’);
txfx_log(‘WordPress loaded…’);
require(‘wp-admin/upgrade-functions.php’);
txfx_log(‘Upgrade functions loaded…’);
wp_cache_flush();
txfx_log(‘Object cache flushed…’);
make_db_current();
txfx_log(‘Database made current…’);
upgrade_160();
txfx_log(‘Data upgraded…’);
$wp_rewrite->flush_rules();
txfx_log(‘Rewrite rules flushed…’);
wp_cache_flush();
txfx_log(‘Object cache flushed…’);
txfx_log(”);
txfx_log(‘Hopefully that did it! DELETE THIS FILE FROM YOUR SERVER NOW!‘);
txfx_log(‘And then, try to access your /wp-admin/

');
        break;
    default :
        txfx_log('This script will attempt to upgrade your database.  It is intended for users of WordPress 1.5 or later.');
        txfx_log('<strong>You should delete this script from your server after you are done using it!</strong>');
        txfx_log('');
        txfx_log('<a href="?step=1">Click here</a> to attempt the upgrade');
        break;
endswitch;
?>