[wp-hackers] plugin activation help

[Andrew Nacin]

On Wed, Sep 1, 2010 at 3:32 AM, Rich Pedley <elfin at elfden.co.uk> wrote:
Fatal error: Cannot redeclare add_user() (previously declared
in C:\inetpub\vhosts\mydomain.com
\httpdocs\store\wp-admin\includes\user.php:23) in C:\inetpub\vhosts\
mydomain.com\httpdocs\store\wp-admin\includes\user.php on line 44

This is a core file, and add_user() is the first function in
wp-admin/includes/user.php... I am wondering if this file is somehow getting
double-included. I really haven't a clue how. Perhaps suggest they download
a new copy of WP and re-upload that one file?