Factual error: Orville says that he born on September 13, 1913, a Friday. That was actually a Saturday. (00:46:10)
Factual error: Haroun swings on a rope to knock Sheherazade's buyer off his horse and uses it for both to escape the slave market. Only thing is: the entrance to the market place is higher up than the auction platform, so the swing should have ended right in the steps, not on the higher ground.
Factual error: When King Cutler shoots his brother near the end of the film, he uses a revolver, a weapon not produced until the next decade.