Well, to get the definitive and final word on this, I sent an email to Christian, who is both the breeder of the rose, and the Director of Research for Weeks Roses. I explained that the AEN was reportedly 'Koko Loco' with a "c," but that the name on Week's website was 'Koko Loko' with a "k," and that we would like to know which is correct. He replied that the correct spelling is 'Koko Loko'.
Perhaps there is a typo in the published AEN if it appears with a "c" there; or perhaps there is a typo on sites that reference the AEN, such as HMF.