In Quran Is Not for Muslims, Mike Ghouse traces much of the "misunderstanding" of Islam to the mistranslation of the Koran/Quran, some of which he says was done purposely. He writes, "It may be worth your while to see the list of the mistranslated verses and how the fear mongers in the market have capitalized on those. The best way to understand Quran is to remember, 'If it is not about justice, mercy and creating harmony', then the translation is wrong. Go back and read it several times, three verse before the 'wrongfully maligned' verse and three afterwards, and read at least three to four translations."
But he goes on to say that the "Quran in Arabic is precisely same and well preserved, but its translation and interpretations are not." So this IS NOT just a misunderstanding of mistranslations. Just like other religions, there are different viewpoints as to the meaning of their sacred scriptures. And it seems to me that a lot of Arabic readers have the most violent interpretations of it.