A little further digging revealed: I had deactivated mailman by # cd /etc/rc2.d; mv S20mailman K20mailman (which I believe is the proper procedure). This may have been causing this bug.
-- [apport] senddigests crashed with IOError in __write() https://launchpad.net/bugs/96863 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
