I'm also having the same problem but double or triple clicking the right key arrow takes you to the next page too. Reading without using the arrow keys on my laptop feels a little weird but I've just been using my wireless mouse to click through the pages.
of the keyboard arrows not working changing the pages?
I have to click on the page and its a big hassle on the computer, its fine for a tablet.
I first started at Takane no Hana, but now it seems like all of them don't like the arrows anymore....