By the way, I've downloaded this one kindle-jailbreak-0.11.N.niluje from the mobileread forum.
OK, cleaned the stuff (as I could ...

).
Copied the update_jailbreak_0.11.N_k3w_install.bin file to the Kindle's root.
Rebooted (to be on the safe side) , ... got the following message:
" The update was not successful.
...
To resume using your Kindle, press the ‘R‘ key on your keyboard.
UPDATE ERROR: 3
"
What did I miss ?