blank page maybe bad configuration php

i'm configuring an auction website... but it show a blank page

it is a subdomain so i'm not really convinced that i configured it correctly

$config = array(

        'Database' => array(

            'driver'     => 'mysql',

            'persistent' => false,

            'host'       => 'localhost', // MySQL Hostname, usually 'localhost'

            'login'      => 'xxxx_admin', // MySQL Username

            'password'   => 'xxx', // MySQL Password

            'database'   => 'xxxx_bid', // MySQL Database Name

            'prefix'     => '', // not usually required, leave blank

            'encoding' => 'utf8' 

        ),

 

 

 

//  *******************************************************************************************

 

 

 

 

        'App' => array(

'license'                => 'xxxx', // Paste your license key

'encoding'               => 'UTF-8',

'baseUrl'                => 'http://bid.xxx.com' // Required only if using subdomain/folder

'base'                   => 'http://bid.xxxx.com' // Required only if using subdomain/folder

'dir'     => '/home/xxx', // Required only if using subdomain/folder

'webroot' => 'webroot',

'name'                   => 'Site Title Here',

'url'                    => 'http://www.bid.xxx.com' // fill this out

'ref_url'                => 'http://www.bid.xxx.com' // fill this out

'nml_url'                => 'http://www.bid.xxx.com' // fill this out

'serverName'             => '', //  this isn't usually needed 

'timezone'               => 'London/England', // check the Time Zone article in the Knowledge Base for the correct syntax

'language'               => 'eng', // Three-letter only, eng = English. 

'email'                  => 'inf@xxx.com', // fill this out and change it to desired email

'currency'               => 'USD', // Three-letter currency code, i.e. GBP, USD, CAD. For other currencies, please see Knowledge Base