I think the best way is to address one error at a time and move on to the next after the first error is confirmed as an error.
I'll go ahead and start with the Koran's claim that the Jews took Ezra as a god (I'll provide the context to the verse so I"m not accused of taking anything out of context):
9:29 - Fight those who believe not in God and the Last Day and do not forbid what God and His Messenger have forbidden -- such men as practise not the religion of truth, being of those who have been given the Book -- until they pay the tribute out of hand and have been humbled.
9:30 - The Jews say, 'Ezra is the Son of God'; the Christians say, 'The Messiah is the Son of God.' That is the utterance of their mouths, conforming with the unbelievers before them. God assail them! How they are perverted!
9:31 - They have taken their rabbis and their monks as lords apart from God, and the Messiah, Mary's son -- and they were commanded to serve but One God; there is no god but He; glory be to Him, above that they associate --
9:32 - desiring to extinguish with their mouths God's light; and God refuses but to perfect His light, though the unbelievers be averse.
9:33 - It is He who has sent His Messenger with the guidance and the religion of truth, that He may uplift it above every religion, though the unbelievers be averse.
9:34 - O believers, many of the rabbis and monks indeed consume the goods of the people in vanity and bar from God's way. Those who treasure up gold and silver, and do not expend them in the way of God -- give them the good tidings of a painful chastisement,
9:35 - the day they shall be heated in the fire of Gehenna and therewith their foreheads and their sides and their backs shall be branded: 'This is the thing you have treasured up for yourselves; therefore taste you now what you were treasuring!'
And here are other translations of verse 9:30:
And the Jews say: Ezra is the son of Allah, and the Christians say: The Messiah is the son of Allah. That is their saying with their mouths. They imitate the saying of those who disbelieved of old. Allah (Himself) fighteth against them. How perverse are they!
And the Jews say: 'Uzair (Ezra) is the son of Allah, and the Christians say: Messiah is the son of Allah. That is a saying from their mouths. They imitate the saying of the disbelievers of old. Allah's Curse be on them, how they are deluded away from the truth!
And the Jews say: Uzair is the son of Allah; and the Christians say: The Messiah is the son of Allah; these are the words of their mouths; they imitate the saying of those who disbelieved before; may Allah destroy them; how they are turned away!
And the Jews say, `Ezra is the son of ALLAH,' and the Christians say, `the Messiah is the son of ALLAH;' that is what they say with their mouths. They only imitate the saying of those who disbelieved before them. ALLAH's curse be on them! How they are turned away.
The Jews say Ezra is the son of God; and the Christians say that the Messiah is the son of God; that is what they say with their mouths, imitating the sayings of those who misbelieved before.- God fight them! how they lie!
The Jews say, "Ezra (Ozair) is a son of God"; and the Christians say, "The Messiah is a son of God." Such the sayings in their mouths! They resemble the saying of the Infidels of old! God do battle with them! How are they misguided!
The Jews say, Ezra is the son of God: And the Christians say Christ is the son of God. They say this (only) with their mouths: They imitate the saying of those who were unbelievers in former times. May God curse them (literally: fight against them)! How can they be so infatuated?
Pleasant.
The historical error in question here is the claim that the Jews have also worshiped Ezra alongside God.
A quick stroll through wikipedia shows that there is no historical evidence that the Jews ever worshiped Ezra.
Abraham Geiger remarked the following concerning the claim that Jews believed Ezra to be the son of God: “According to the assertion of Muhammad the Jews held Ezra to be the Son of God. This is certainly a mere misunderstanding which arose from the great esteem in which Ezra was undoubtedly held. This esteem is expressed in the following passage ‘Ezra would have been worthy to have made known the law if Moses had not come before him.’ Truly Muhammad sought to cast suspicion on the Jews’ faith in the unity of God, and thought he had here found a good opportunity of so doing.”
http://en.wikipedia.org/wiki/Uzair#Jewi ... literature
Hopefully there won't be too much trouble with this clear error. Muhammad (or the author(s) of the Koran) misunderstood Judaism and Christianity to an extraordinary degree. In fact, the next historical error I plan on addressing will cover yet another theological mistake the Koran makes on Judaism.