Hmm - it looks like the Chronicle of Higher Education puzzles are about 2 weeks or more behind ... I think this is what is throwing Black Ink off with regard to the expected URL:
http://chronicle.com/review/crossword/%Y%m%d.puz
Black Ink uses the URL format along with the current date to try to guess the right URL for the latest puzzle. Since the puzzles come out on Fridays, one would think for instance that there was a puzzle to download on March 30, but there isn't one yet.
I'm not sure what the best solution for this would be. Black Ink would have to have a more complicated means of specifying the puzzle URLs than the current setup.