/usr/local/mailman/spam needs to exist with the same ownership and priveliges as it's sibling directories. This directory is used when an administrator 'discards' and email but chooses to keep a copy of it stored. If this directory doesn't exist, mailman gives you a python error message. Reproducible: Always Steps to Reproduce:
which version are affected ?
fixed mailman-2.1.2 & -r1