Other mistake: In the scene when Sherlock Holmes and his crew are running through the forest, the barrel of "Little Hansel" can be seen being raised up to 50°, which would cause a parabolic trajectory, but the shell travels in a horizontal path as it blasts through a tree and past Holmes. (01:30:25)
Other mistake: In Moriarty's college study, the white King and Queen chess pieces are actually on the wrong squares. Queen starts on her own color.
Other mistake: When Holmes and his gang are running from the Germans through the forest, one of Moriarity's German lackeys yells that it is time to introduce them to "Little Hansel" (in subtitles). Strangely, what he really yelled was, "zu viele Fuchse fur euch paar Huhner," or "too many foxes for those few chickens." Not sure why they made such a change in dialogue (where the German phrase was ever thought to fit in).
Chosen answer: That's the key code for his fortune concealed in his library. The one Mrs Watson uses to relay to Inspector Lestrade. Like the book reference numbers in a public library.