Anzeigen Benutzer aktualisieren wirft Fehlermeldung aus

<<<<<<<<174ec68f0de0e8465471a7654e5fe5a3b56a78c3<<<<
Sun, 17 Jul 2016 17:54:51 +0000
Message: Could not execute prepared statement: SQLSTATE[HY000]: General error: 2031 
File: /var/www/vhosts/ac-cafe.de/httpdocs/wcf/lib/system/database/statement/PreparedStatement.class.php (97)
PHP version: 5.6.23
WCF version: 2.1.11 (Typhoon)
Request URI: /acp/index.php?worker-proxy/&&
Referrer: http://www.ac-cafe.de/acp/index.php?rebuild-data/&
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:48.0) Gecko/20100101 Firefox/48.0
Information: ""
Stacktrace: 
  #0 /var/www/vhosts/ac-cafe.de/httpdocs/wcf/lib/data/user/UserProfileAction.class.php(375): wcf\system\database\statement\PreparedStatement->execute(Array)
  #1 [internal function]: wcf\data\user\UserProfileAction->updateUserOnlineMarking()
  #2 /var/www/vhosts/ac-cafe.de/httpdocs/wcf/lib/data/AbstractDatabaseObjectAction.class.php(196): call_user_func(Array)
  #3 /var/www/vhosts/ac-cafe.de/httpdocs/wcf/lib/system/worker/UserRebuildDataWorker.class.php(55): wcf\data\AbstractDatabaseObjectAction->executeAction()
  #4 /var/www/vhosts/ac-cafe.de/httpdocs/wcf/lib/acp/action/WorkerProxyAction.class.php(93): wcf\system\worker\UserRebuildDataWorker->execute()
  #5 /var/www/vhosts/ac-cafe.de/httpdocs/wcf/lib/action/AbstractAction.class.php(49): wcf\acp\action\WorkerProxyAction->execute()
  #6 /var/www/vhosts/ac-cafe.de/httpdocs/wcf/lib/action/AJAXInvokeAction.class.php(63): wcf\action\AbstractAction->__run()
  #7 /var/www/vhosts/ac-cafe.de/httpdocs/wcf/lib/system/request/Request.class.php(58): wcf\action\AJAXInvokeAction->__run()
  #8 /var/www/vhosts/ac-cafe.de/httpdocs/wcf/lib/system/request/RequestHandler.class.php(139): wcf\system\request\Request->execute()
  #9 /var/www/vhosts/ac-cafe.de/httpdocs/acp/index.php(10): wcf\system\request\RequestHandler->handle('wbb', true)
  #10 {main}
<<<<