Continuity mistake: When the gang first arrives at the Vatican (as soon as the "map" shows them travel across the table to Italy), there is a very quick shot of them walking down an alley. Scotty says "there it is" and they walk toward a door with a sign above it (in English, for some reason) that says "Summer at Sea". The shot then changes and they are walking up to the Vatican guards. I guess there was supposed to be a scene where they went to the Summer at Sea office to find "Mike" but it was deleted. It wouldn't make sense, since they knew she was going to the Vatican anyway.
Revealing mistake: When flashing to hitch a ride, black tape can be seen underneath Michelle Trachtenberg's top to preserve her dignity.
Continuity mistake: At the Vatican, when Scotty first sees Mieke, she has her hair in a ponytail, and her hair is straight. After the sex in the confessional, as she is leaving to catch her boat, her hair is curly.
Continuity mistake: The mail Scott writes when he is drunk is not the one Mieke receives. You can see exactly that Scott writes "freak", but the mail Mieke receives is full of typing errors. One of them spells freak as "fraek".
Other mistake: Right after the scene where they are chased by a bunch of naked guys at the nude beach, they're sitting in a train and we can see Scott leafing through his past e-mail correspondence with 'Mike'. If you look closely, you'll notice that the third page is the same as the first page.
Continuity mistake: The word "zussamen" which is shown close-up, when Scott reads an e-mail from Mieke after the graduation party, is not written in the e-mail that can be seen a few shots earlier.
Factual error: In addition to the error revealed before: The group approaches the Vatican Museums from the left, which is impossible because of the Vatican City Wall standing there.
Continuity mistake: In the scene where Cooper visits the Amsterdam pleasure house, he is given a safe word. When he is given this word, the woman directly on his left, the one in the pink sparkle shirt, you can see her breasts and not under her shirt. When she goes to strap his ankle to the metal structure in the next shot, her breasts are under her shirt. When she straps his wrist to the same structure two seconds later, her breasts are back out again.
Factual error: After the climax at the Vatican, before the main characters are seen sitting and having a drink, there is a brief shot from inside the "Galleria Vittorio Emanuel II", which is in Milan, not Rome.
Continuity mistake: When Scotty wakes up on the double-decker bus, his hair and the ribbons on the trophies aren't moving at all. In the next aerial shot they are all flapping in the wind.
Deliberate mistake: When Madame Vandersexxx writes the safe word onto the piece of paper, she writes it way too fast and scribbly for it to be perfectly written as shown when there is a close up of it when Cooper is reading it.
Factual error: When the guys drive from Bratislava to Berlin it shows them driving past the Black Forest on the make-shift map. In reality the Black Forest is located in the south-western most corner of Germany near the borders to France and Switzerland, so driving in a more or less straight line from Bratislava to Berlin would make them miss the Black Forest by about 550 km (342 mi).
Character mistake: The name on the sign of the pub/private members club of the Manchester United fans is spelt incorrectly: It should read "The Feisty Goat" but Feisty is misspelled on the sign as "Fiesty" instead.
Factual error: When the guys fly from the USA to London, UK, they fly with the German airline Lufthansa. The same airline takes them from Rome, Italy, back to the USA. Lufthansa is only allowed to directly connect US cities to German cities, not including third countries.
Factual error: In the very beginning of the trip, a map of Europe is shown. It shows Bosnia and Herzegovina as a separate country, yet it shows Croatia and Yugoslavia as one country. Bosnia and Herzegovina split from Yugoslavia after Croatia, so if Croatia and Yugoslavia are a single country, then Bosnia and Herzegovina should not be separate either.
Factual error: When Scott and Cooper throw the burning hat in the fireplace, the smoke is seen coming out of the chimney in the Sistine chapel. Though this adds a bit of hilarity, the chimney is only able to be used when constructed in preparation for the Conclave of all conclaves, the election of the new pope.
Audio problem: When the four friends are in a French restaurant and Scotty, Cooper, and Jenny are trying to persuade Jamie to join them on their quest to Germany, Scotty's line is heard as "I Love Denmark," but his mouth forms the words "I Love Amster," as if he was in the process of saying Amsterdam before the shot changed.
Continuity mistake: On the beach, Jennifer starts to untie her bikini top after taking off her shirt. When her brother yells to warn her and the camera pans back to her, her top is still fully tied.
Visible crew/equipment: In the scene where Scotty and Cooper are waking up on the bus, behind their heads is a shiny soccer trophy where you can see a man holding a microphone and another guy with a camera.
Character mistake: Scott says that England is an island, which is incorrect; England, along with Scotland and Wales, is one of the three major divisions of Great Britain, which is an island.
Chosen answer: It was made for the movie but you can now find it all over the 'net. Try a Google search.