Factual error: We're told over and over that Vicky is an expert on Barcelona and Catalonia, for she has written a thesis. She visits Avilés (Asturias) with Juan Antonio, where he tells her he was born a few blocks from there; however, during their dinner at night the actress mistakes and tells him that he's from Catalonia, instead of Asturian. Anyone with a such an expertise on Catalonia will know that. Besides, it's not real life, but a screenplay, so either Woody Allen screwed up, or the actress did.
Factual error: The "corn" they are growing is not corn, just crabgrass.
Factual error: The bar shown in Iqualuit is not real. Iqualuit only has 6100 or so people, and there is no bar like the one shown in the movie. The building is wrong - it doesn't even look like any buildings in Iqualuit. There is one bar that looks nothing like the movie, one Legion, and a bar in the hotel in Iqualuit.
Factual error: Chicago is the setting of the movie - the distance from Chicago to Georgetown is not as long as depicted.
Factual error: In the film, the train is hauled by diesel locomotives on a single track not electrified line. Since early 2000 the Trans-Siberian is double-track and fully electrified.
Factual error: Near the end of the movie, a front view of the overdosing/overdosed twins shows Robert putting the dying twin's head on his lap. A close-up of the dead twin shows blood covering most of the left side of her face and a blue tinge on most of the right side, apparently meant to indicate developing livor mortis (bluish color after death). This twin just died, so it is too early for livor mortis to be visible. Livor mortis is not visible to humans until about two hours after death, but the process does begin sooner (about 20-30 minutes after death). Moreover, the writer failed to show the first stage of death - pallor mortis. The twins were Caucasians with blonde hair, so the dead twin would first turn pale (from blood draining from veins in the skin) about 15 minutes after death. The sudden oozing of blood from the dead twin's forehead was also not an accurate portrayal - she was dead, so her heart no longer pumped blood (so gravity takes over, draining blood). (01:39:58)
Factual error: As the cars travel over 1950s Westminster bridge, the modern red route lines can be seen on the road.
Factual error: In the streetcar scene a passenger is a soldier wearing a US Army green uniform with a CIB, Comat Infantry Badge. At the time US uniforms were brown and there is no plausible reason for this US soldier to be in that country.
Factual error: When Mulder avoids hitting the truck, in the shot from the inside of the car he turns the wheel full left which means that the car should start to spin anticlockwise. However, in the next outside shot the car spins clockwise. (01:16:25)
Factual error: During the opening credits. An LCD screen is shown with lat/long coordinates. The movie takes place in the Persian Gulf. The coordinates are in the vicinity of Oceanside, CA.