I wrote "Kama vitabu vikipotea utalipa." That should be correct. I agree that I don't need to add the "kama" but in previous examples and translations the Duolingo folks used "Kama" with the "ki" (conditional) tense. Duolingo should be consistent.
The course is in limited beta, which means it still needs a bit of work. Use the report function (the button next to discuss sentence) if you feel there is something wrong with the sentence or if your translation should be accepted. The comments is not really the place.