Well, in that case, if its the old cpanel, that changes things, it IS localhost, login to the old cpanel, scroll down to mysql databases, and then the config page should look something like this:
Code:
<?php
// phpBB 2.x auto-generated config file
// Do not change anything in this file!
$dbms = 'mysql4';
$dbhost = 'localhost';
$dbname = 'dbname';
$dbuser = 'dbuser';
$dbpasswd = 'password';
$table_prefix = 'a*******_';
define('PHPBB_INSTALLED', true);
?>
Change the dbname, dbhost, password, and a*******_ to match your account.