documented paths don't agree with reality

The Ubuntu packaged documention seems to mirror the Courier documentation without taking into account the special paths used for the build.

/usr/lib/courier/libexec/courier/webmail/webadmin is actually at /usr/lib/courier/courier/webmail/webadmin .
/usr/lib/courier/etc/webadmin/password is actually at /etc/courier/webadmin/password .

I suspect something similar is preventing me from successfully logging in on Administrative Login page

I am running Ubuntu 12.04 with Cherokee 1.2.101 .
I have installed Courier-ESMTP (0.66.1), -POP3S, -IMAPS and -webadmin from the Ubuntu Software Centre, and I'm now trying to get webadmin working so that I can configure the Courier settings.

The instructions at the courier website say that I should use the installation instructions that come with the packaged pre-built binaries, but they are the same, despite the file system layout being somewhat different.

I can get the Administrative Login screen up, and the installation process already asked me to preset the password, and /etc/courier/webadmin/password contains my password, but the login page seems to reject my password and returns "302" and reloads the login page without any error message.