Error Creating tasks out of Mails (FF)

[Paul Becker]

Dear Members of the Kolab Mailinglist,

we have a strange issue regarding creating tasks by Mails in Kolab an hope you may help us. Our customer - using Roundcube Webmail 1.0-38.1.el6.kolab_3.2 - wants to create tasks out of his Inbox Mails but unfortunately after wanting to save the new task we get the error "An error occured! Files couldn't be saved." (We are using the German language, literally it is called: "Ein Fehler ist aufgetreten! Daten konnten nicht gespeichert werden"). This problem seems to occur just using Firefox (regardless of the OS version) 31+ (I have tested version 32 and 33 nightly). Has anyone experienced something similar or might have been trough this problem? The debugger tools just say:

 getUserData() und setUserData() sollten nicht mehr verwendet werden. Verwenden Sie stattdessen WeakMap oder element.dataset. requestNotifier.js:63
"HTTP POST: ./?_task=tasks&_action=mail2task" app.js:557
"HTTP POST: ./?_task=tasks&_action=task" app.js:557
"this.display_message("Daten konnten nicht gespeichert werden.","error",0);
"

Of course I have disabled all addons. Help would be appreciated. Thank you in advance.

Regards,
Paul Becker