wbb3 problem!

PHP-Code:
Fatal error: variable 'boardStructure' does not exist in cache resource 'board'

You get more information about the problem in our knowledge base: http://www.woltlab.com/help/?code=11008
Information:

error message: variable 'boardStructure' does not exist in cache resource 'board'
error code: 11008
file: /var/www/htdocs/ks4712/html/wcf/lib/system/cache/CacheHandler.class.php (138)
php version: 5.2.6-1+lenny9
wcf version: 1.1.6 pl 3 (Tempest)
date: Sat, 21 May 2011 00:35:11 +0000
request: /index.php?page=Index
referer:
Stacktrace:

#0 /var/www/htdocs/ks4712/html/lib/data/board/Board.class.php(529): CacheHandler->get('board', 'boardStructure')
#1 /var/www/htdocs/ks4712/html/lib/data/user/AbstractWBBUserSession.class.php(92): Board::inheritPermissions(0, Array)
#2 /var/www/htdocs/ks4712/html/lib/data/user/WBBUserSession.class.php(112): AbstractWBBUserSession->getGroupData()
#3 /var/www/htdocs/ks4712/html/wcf/lib/system/session/UserSession.class.php(62): WBBUserSession->getGroupData()
#4 /var/www/htdocs/ks4712/html/lib/data/user/WBBUserSession.class.php(58): UserSession->handleData(Array)
#5 /var/www/htdocs/ks4712/html/wcf/lib/data/DatabaseObject.class.php(24): WBBUserSession->handleData(Array)
#6 /var/www/htdocs/ks4712/html/wcf/lib/data/user/User.class.php(67): DatabaseObject->__construct(Array)
#7 /var/www/htdocs/ks4712/html/wcf/lib/system/session/UserSession.class.php(33): User->__construct(1, NULL, NULL, NULL)
#8 /var/www/htdocs/ks4712/html/lib/data/user/WBBUserSession.class.php(51): UserSession->__construct(1, NULL, NULL)
#9 /var/www/htdocs/ks4712/html/wcf/lib/system/auth/UserAuthDefault.class.php(79): WBBUserSession->__construct(1)
#10 /var/www/htdocs/ks4712/html/wcf/lib/system/auth/UserAuthDefault.class.php(59): UserAuthDefault->getUserAutomatically(1, 'ea98976edf59a2f...', 'WBBUserSession')
#11 /var/www/htdocs/ks4712/html/wcf/lib/system/session/CookieSessionFactory.class.php(46): UserAuthDefault->loginAutomatically(true, 'WBBUserSession')
#12 /var/www/htdocs/ks4712/html/wcf/lib/system/session/SessionFactory.class.php(73): CookieSessionFactory->create()
#13 /var/www/htdocs/ks4712/html/lib/system/WBBCore.class.php(200): SessionFactory->get()
#14 /var/www/htdocs/ks4712/html/wcf/lib/system/WCF.class.php(98): WBBCore->initSession()
#15 /var/www/htdocs/ks4712/html/global.php(18): WCF->__construct()
#16 /var/www/htdocs/ks4712/html/index.php(7): require_once('/var/www/htdocs...')
#17 {main} 