Installing QMailAdmin from FreeBSD ports also installed the ezmlm-idx package. QMailAdmin worked quite good except when creating mailing lists. It showed an error like No mailing lists found (translated from Dutch) after submitting a request to create a mailing list.

Luckily, the httpd error logs had the following lines in it.

It appeared that /usr/local/etc/ezmlm/ezmlmrc.sample was not renamed to /usr/local/etc/ezmlmrc. I missed any documentation on the existence of this file, but after renaming it to the right name, mailing list creation just worked fine. Don't worry about the fact that httpd-error.log mentions the bin directory, having it in etc/ezmlm is enough.