Revealing mistake: In the beginning, the harem teacher and his pupils read the story (which becomes the movie) from the book Arabian Nights. The huge book propped up in front of the old man, though, is only an empty cover with no pages at all.
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: In the desert harem, a cacadu can be seen sitting in a hanging loop. Cacadus are native to Australia, though, and in the 9th or 10th century AD (the period Haroun al Rashid lived in), Australia did still not exist in the then-known world.
Factual error: In the beginning of the film, the famous Taj Mahal can be seen through a window in the harem. But the famous tomb palace is to be found in India, while Bagdad is located in Persia. Obviously an attempt to create an exotic atmosphere.
Suggested correction: The building shown is one based on the Taj Mahal not the actual one.
Continuity mistake: During the final battle scene, there are two shots showing a kicking horse lying on the ground, with one of Haroun al Rashid's soldiers (dead, most likely) pinning it down at its neck. In the first shot, one of Kamar's soldiers lies in front of its flailing hooves, but in the next shot, an al Rashid warrior drives a Kamar soldier backwards, tripping him across the lying horse - and the Kamar warrior from the first shot is gone. My guess is that the cuts were originally in reversed order but re-arranged for the scene.
Plot hole: When the acrobats free Haroun at the smithy, they lure his guards into the blacksmith's house singly or in pairs and knock them out. however, the sound of the blows and the rapid succession they are called for should have made the guards suspicious.
Continuity mistake: When Kamar is assassinated by Nadan the Grand Vezier, he slips into the harem basin with his left arm bend towards the dagger in his back. But in the next shot (as the blood spills into the water), his left arm is pointing forward.