It looks like back_mysql.py and back_anydbm.py both had
some uses of True and False creep in at some point
during the 0.7 series.  This, of course, crashes when
using Python 2.1.

(I guess I can't find anywhere on the website where you
actually say what version you support, never mind
whether Python 2.1 is supposed to work, but since
everything else seems to be fine...)