[Deaths]

You can try the following things:
Replace

%items = (
      Nickname => $ENV{REMOTE_USER} || $config->{default_nick},

By

%items = (
      Nickname => $bbuserinfo[username],

OR

Replace

# default nickname, a ? is replaced with a random number
default_nick = user???

by

# default nickname, a ? is replaced with a random number
default_nick = $bbuserinfo[username]

One of the two should work.

In both cases you would need to add this near the top of the document (where the vars are set)

PHP Code:

require_once('./global.php'); 


Or, when your code is in HTML or ASP (which I highly doubt)

PHP Code:

<?php require_once('./global.php'); ?>