An Exception was thrown while handling an Exception:

Error: Class "wcf\system\exception\ErrorException" not found in /var/www/vhosts/vdr-portal.de/httpdocs/lib/system/WCF.class.php:341
Stack trace:
#0 [internal function]: wcf\system\WCF::handleError()
#1 /var/www/vhosts/vdr-portal.de/httpdocs/lib/core.functions.php(178): touch()
#2 /var/www/vhosts/vdr-portal.de/httpdocs/lib/core.functions.php(270): wcf\functions\exception\logThrowable()
#3 /var/www/vhosts/vdr-portal.de/httpdocs/lib/system/WCF.class.php(313): wcf\functions\exception\printThrowable()
#4 [internal function]: wcf\system\WCF::handleException()
#5 {main}

was thrown while:

wcf\system\exception\SystemException: There is no access to the system temporary folder due to an unknown reason and no user specific temporary folder exists in /var/www/vhosts/vdr-portal.de/httpdocs/! This is a misconfiguration of your webserver software! Please create a folder called /var/lib/php/sessions using your favorite ftp program, make it writable and then retry this installation. in /var/www/vhosts/vdr-portal.de/httpdocs/lib/util/FileUtil.class.php:111
Stack trace:
#0 /var/www/vhosts/vdr-portal.de/httpdocs/lib/system/WCF.class.php(174): wcf\util\FileUtil::getTempFolder()
#1 /var/www/vhosts/vdr-portal.de/httpdocs/global.php(15): wcf\system\WCF->__construct()
#2 /var/www/vhosts/vdr-portal.de/httpdocs/index.php(10): require_once('...')
#3 {main}

was handled.