Christianity still doesn't have its issues figured out -face palms-. No religion does, really. Its not actually the religions fault, once you break it down, so much as its the fault of the people who constantly misinterpret, intentionally interpret doctrine, or have their own ideas on what should or should not be done. There are so many different factions of protestants and catholics I don't even know where to start and many of them hate each other. Muslims are no different. The only reason it might seem like things have been "solved" is because governments (western anyways) and people finally got so fed up with religion ruling their lives, that they forced governments to have nothing to do with religions thus taking away a religions overt powers of control over a population; best example Pre-Catholic as a name/Christians during the Roman Empire/Byzantine Empire up to sometime before WWI (fuzzy on dates when the Europeans finally stripped Catholicism of its power).
So I side with Wolfy on this one, as long as there are people constantly creating new factions of a religion and people who cannot settle on anything, and constantly hating others, there will be no peace.