Other mistake: When Giosuè discovers the German boy in the metal box Guido says that his name is Schwarz (Black). The German subtitles translate the name as Schwanz (Tail or - rather - Dick), and that's how both Guido and Giosuè refer to the boy later. Even if the different naming later was intended the first subtitling was too anticipatory.
Other mistake: When Guido drops Dora at home after he had "kidnapped" her from the opera the rain has stopped. She mentions his wet hat, he takes it off and puts it back on, and when he bends forward a substantial trickle comes running off the brim. There should be no water left (if any) after he had taken the hat off.
Other mistake: When Guido decides to leave the camp with Giosue, he stops by the box Giosue will hide in, and says they will win 60 points if they get through the night. When Giosue asks how many points they have ("Quanti punti abbiamo?"), you can see Guido mouth " - ti abbiamo" along with Giosue.