None at all...
UPDATE:
Now, for some inexplicable reason, it works. I redid the procedure several times, always the same result. Then I went to the folder where mobipocke tactually stores the files on my computer, grabbed the file there and put it onto the SD card and it works. All the other files were transferred using the mobipocket "Send to..." function, and worked, just this one wanted a special treatment for some reason...