Flashcards not working with Ilias 5.2

[millerlight]

I am new to ILIAS.
Tried to install Flashcards and Ilias 5.2 offers the plugin actions: information/update/uninstall.
When I try to update I get the following message:

Error thrown with message "Call to a member function update() on null"

Stacktrace:
#6 Error in /var/www/html/ilias/Services/Component/classes/class.ilObjComponentSettingsGUI.php:520
#5 ilObjComponentSettingsGUI:updatePlugin in /var/www/html/ilias/Services/Component/classes/class.ilObjComponentSettingsGUI.php:90
#4 ilObjComponentSettingsGUI:executeCommand in /var/www/html/ilias/Services/UICore/classes/class.ilCtrl.php:188
#3 ilCtrl:forwardCommand in /var/www/html/ilias/Services/Administration/classes/class.ilAdministrationGUI.php:247
#2 ilAdministrationGUI:executeCommand in /var/www/html/ilias/Services/UICore/classes/class.ilCtrl.php:188
#1 ilCtrl:forwardCommand in /var/www/html/ilias/Services/UICore/classes/class.ilCtrl.php:150
#0 ilCtrl:callBaseClass in /var/www/html/ilias/ilias.php:21