At the end of the movie when Darcy is reading her journal it says "November 10 Friday," and the movie came out in 2001. But the only dates that would have a November the 10 on a Friday are: 2000, 1995, 1989, 2090, 2084, 2079 , 2073, 2062, 2056, 2051, 2045, 2034, 2028, 2023, 2017, and 2006. I used my laptop calendar to figure that out.
The film was released in April '01, so was most likely filmed in 2000. In which case they got it right, just didn't take into account the post-production period. Also, I don't know how old the book it's based on was when the film was made. Maybe the author wrote it in 1995 and they took the date straight off the page?