mail/courier-imap does not start after latest update

[Daniel Eggert <danieleggert%mac.com@localhost>]

I have updates courier-imap to
        courier-imap-4.1.1nb2
        couriertcpd-0.53.2nb1

but now, when I start, I get:
        Jun 25 10:31:27 kelvin couriertcpd: exec: No such file or directory
in /var/log/maillog.

What it that file, that can not be found? How can I find out?

This used to work with courier-imap-4.1.0.

Thanks in advance, for any input.

/Daniel