Sorry about that, my first post... And sorry about not being clear enough: The difference about this line is that it's a single word. No spacing. Longer than the page. And instead of breaking and continuing on the next line (as in ADE and Bluefire), in iBooks it just keeps going...
Maybe the solution is something really simple, but right now i can't think of anything else than adding a * or a so the line can break. But that doesn't really look very good, since the line with the hyphen then won't justify like the others.
It's also really disturbing since the other readers breaks the line, so why doesn't iBooks? Why just keep going?