KOrganizer is unusable after upgrade to 4.7.4

[Mirosław Zalewski <miniopl@poczta.onet.pl>]

Hi

I am using Debian testing. After today's upgrade, I finally got to run KDE 
4.7.4. 

Unfortunately, all my Korganizer info disappeared. I mean - Calendar and to-do 
list in Kontact does not display anything. All information are safe in
~/.kde/share/apps/korganizer/std.ics file.

When I try to add new to-do, I get error message:
"No calendars found, event cannot be added."

How can I get my calendar back? I don't think I ever changed Korganizer 
setting in any way. They are pretty much default.

I tried on new user (without any files or directories in ~), and I got the same 
error message when trying to add new to-do entry.

It seems similar to KDE bug #279550 
(<https://bugs.kde.org/show_bug.cgi?id=279550>). Unfortunately, there was no 
responses to that message.

Any help would be appreciated. If you need any further information, please 
tell me what (and how do I get them for you).
-- 
Best regards
Mirosław Zalewski