My experience installing Duokan Lite (1014.1225) on Kindle 3 Wi-Fi ("Keyboard") with latest firmware (3.3) in case it's useful for reference:
-It failed in the first try. I had just unistalled old non-lite Duokan and updated Kindle firmware to 3.3.
-I reset it to factory defaults (be careful! this erases all your books from the disk) and tried again: this time it worked. (The progress bar gets stuck for some minutes at the same point during the process, but just give it its time.) I have now Duokan Lite on firmware 3.3. No problems so far.