I solved the downloading problem in that way:
I downloaded an older version with links in this thread and installed duokan and then I updated OT, so now I have the newest version 2012-10-19.16744.
I had one problem during install-process: In the Installation manual is written that at a certain point you need to start duokantool.exe and insert your serial number. I spend several hours to search for the file "duokantool.exe", but could not find it for downloading. So I only rebooted the device and what surprise, duokan was installed without this step
I changed the language to my own language (german) with the help of this video:
http://www.youtube.com/watch?v=OT8VHJYo1xc
Some people here said that the contrast in older duokan versions is better than in the new one. I dont know the older versions, but in this version the contrast seems to be good.
In which older version was the contrast better?
I am now glad to have a K4NT which supports epub
