Continuity mistake: During a conversation a clock can be clearly seen in the backround and the time is 11:50, the scene cuts to a closeup of Nick Nolte speaking, then back to the wider shot and it's suddenly become 11:55 in a matter of seconds. But it doesn't stop there, it again cuts away for a few seconds and when it comes back to a a shot of the clock it now reads 11:40.
Audio problem: When Augusto has the nightmare with the voice counting in Italian (right before he realizes that the two enzymes are the same), the word for 16 is wrong. The voice says "diciassei," but the word is actually "sedici."
Deliberate mistake: When Michaela reads "The Once and Future King" to Lorenzo, she doesn't start at the beginning, even though she's never read him that book before. Not only does she not open the book to the first page, the words she reads are not at the beginning of the book (I believe they are about three or four chapters in).