Fatal error: PHP notice in file /home/www/web577/html/Board/lib/system/session/CookieSessionFactory.class.php (121): Use of undefined constant COOKIE_PREFIX - assumed 'COOKIE_PREFIX'

Information:

error message: PHP notice in file /home/www/web577/html/Board/lib/system/session/CookieSessionFactory.class.php (121): Use of undefined constant COOKIE_PREFIX - assumed 'COOKIE_PREFIX'
error code: 0
file: /home/www/web577/html/Board/lib/system/WCF.class.php (255)
php version: 5.2.17
wcf version: 1.0.11 pl 3 (Horizon)
date: Thu, 17 Apr 2014 07:07:39 +0000
request: /forum/index.php?page=Thread&threadID=148
referer:

Stacktrace:

#0 /home/www/web577/html/Board/lib/system/session/CookieSessionFactory.class.php(121): WCF::handleError(8, 'Use of undefine...', '/home/www/web57...', 121, Array)
#1 /home/www/web577/html/Board/lib/system/session/SessionFactory.class.php(61): CookieSessionFactory->readSessionID()
#2 /home/www/web577/html/forum/lib/system/WBBCore.class.php(201): SessionFactory->get()
#3 /home/www/web577/html/Board/lib/system/WCF.class.php(91): WBBCore->initSession()
#4 /home/www/web577/html/forum/global.php(18): WCF->__construct()
#5 /home/www/web577/html/forum/index.php(7): require_once('/home/www/web57...')
#6 {main}