Hi Teom@n,
The way I converted files from
http://www.babylon.com/free-dictionaries/ is using stardict-editor and penelope. I'm on linux, but I there is probably a Windows version too. You need to get a terminal window. Check the site if there are dictionaries (.BGL) that you can use and download them. Then:
stardict-editor
#An editor will be opened where you need to browse and select you .BGL file(Babylon Dictionary)
#In the bottom of the opened application you select BGL file and click on Build button
#It will create a file with an extension .babylon.
#Next browse and select this file
#In the bottom of the opened application you select Babylon file and click on Build button
#That's it. It will create 3 files (.dict.dz, .idx, .ifo) in the current directory
# Now use penelope to convert to kobo format
# <from> and <to> are 2-letter language codes
python <directory of penelope>\penelope.py -p <idx name without extension> -f <from> -t <to> --output-kobo
Hope this helps.