Corrected entry: In the scene near the end of the movie, the Frankenstein monster was tied up on top of Dracula's Castle. After the first bolt of lightning hit him, he tried to break the chains (or belts?) and succeeded except for his left leg, which was still chained up around his ankles. Suddenly, a second bolt of lightning struck him. The next shot (from afar)shows that the Frankenstein monster's whole body is still tied up to the bed.
Corrected entry: In the scene when Carl and Van Helsing arrive in Transylvania, Carl is measured by the Grave Digger as 5 foot 7 inches. In 1880s Europe, most people used the metric system.
Correction: You have supplied your own correction: "MOST people used the metric system". The grave digger is one of the ones who didn't.
Corrected entry: Throughout the movie, Dracula's 3rd finger on his right appears and disappears.
Correction: When looking closely at Dracula's right hand throughout the movie, you will see that the 3rd finger is always there only until the point when he mentions the ring. In truth, when Dracula shows where his ring WOULD have been, he was only keeping the 3rd finger down to show it. The finger was never really cut off.
Corrected entry: Budapest was originally called Buda-Pesth and it still was at the time the film is set, even if it DOES say Budapest on the map (sorry, but I'm not sure when it changed)
Correction: It still is Buda-Pesht, but how many Americans know that? I've also seen it spelled different ways in English (your Pesth, my Pesht, the usual Pest), so they had to use the format most common to the largest portion of the audience just so the viewer would know what they were referring to. Besides, who's to say that VH didn't have an American made map?
Corrected entry: Van Helsing's plan was to kill Dracula and have the antidote injected by midnight, within the time that it takes for the clock to chime 12 times. The fight scene took much longer than that, but the antidote still worked later.
Correction: The antidote cures the curse of the werewolf, no matter how long one has been a werewolf. If it only worked until the final stroke of midnight during the first full-moon, there would be no reason of keeping it, as it would be useless after a certain period of time. And at that time, no werewolves were working for Dracula (Both of the others were killed)
Carl says that they have until the stroke of midnight to get the antidote into Van Helsing before he's stuck with lycanthropy forever.
I assume Carl was mistaken, as it would be quite useless for Dracula to have the antidote if it worked only for a short time from first transformation to the last stroke of midnight. Dracula had the antidote to cure werewolves who opposed him before getting bitten, so obviously the antidote could be used any time. And it indeed worked even after the last stroke of midnight.
I'd gotten the idea that the curse is permanent after the 12th stroke of midnight specifically during a full moon and they become Dracula's slave and a permanent wolf and then the cure is useless. Dracula keeps the cure in case there is a werewolf that can resist his dominance, but after the 12th stroke of midnight they are his slave forever and he doesn't need the cure anymore (except maybe a new werewolf). This is what would happen to Van Helsing as well. Carl and Anna only say they have to kill Van Helsing after midnight, certainly if he didn't manage to kill Dracula, or he becomes his most powerful slave. They say it probably because he would loose control and becomes Dracula's slave and become too dangerous to approach. They can't have the werewolf loose onto the world even if he does kill Dracula, as he would still lose his control and be a permanent Werewolf.
Correction: Frankenstein's Monster never made an attempt to break out of the metal bracelets that bound him to the table (he didn't even try to break out of the chains while riding in the stage coach but asked Carl to unlock him). Van Helsing freed him from every lock except his left leg (not the monster himself) and when the lightning struck a second time the force pushed him back flat up against the table again.