biber-darwin:197> INFO - This is biber 0.9.3
 biber-darwin:198> INFO - Logfile is 'chapter-five-ifye-biblatex.blg'
 biber-darwin:205> INFO - === Biber version 0.9.3
 biber-darwin:206> INFO - === Wed Feb 8, 2012, 10:13:15
 Biber.pm:320> INFO - Reading chapter-five-ifye-biblatex.bcf
 Biber.pm:596> INFO - Found 42 citekeys in bib section 0
 Biber.pm:2435> INFO - Processing bib section 0
 Biber.pm:2522> FATAL - Error loading data source package 'Biber::Input::file::bibtex': data source /var/folders/Tc/TcIS3EbA2RWfXU+8ZLmmZU+++TM/-Tmp-/par-amrys/cache-87e3be796a0b125e5c85a2f02054ca3cdca74f86//inc/lib/Biber/Input/file/bibtex.dcf not found in .
Compilation failed in require at (eval 79) line 2.
You notice that a typeset paper does in fact result (even if a program like TeXShop won’t automatically open it for you because of the error); but instead of typesetting your references, it simply displays cite-keys. Infuriating! Nothing appears to be wrong with your .tex file. After banging your head against the wall trying to figure out why biber won’t finish, you do a bit of searching, and discover that this is just a weird thing where biber doesn’t clean up after itself.
See that crazy path up there in the biber log?
It’s that par-amrys (or, rather, par-[username]) directory that is giving you the business. Delete it. (On a Mac, you’ll either need to do this in the terminal by cd‘ing to that -Tmp- directory and rm -rf‘ing the par-[username] directory; or make sure that the Finder is displaying “hidden” system files so that you can navigate to it in the GUI.)
And, voilà! You will now be able to typeset your references properly.