It's definitely Karyo. It's true that the "ka" part can sometimes be read "hana", but in this case we can be 100% sure - the hiragana reading is actually included on the cover. It's the small white text at the top left.
There's a Karyo High School in Yamaguchi, by the way.
I have OS 10.4.11 intel. I use UnrarX or RAR Exapnder 2 for rar files, and Jigsaw 3.0 for anything else. Never found anything I couldn't join with these.