dpkg --purge leaves empty directory.

[Peter S Galbraith <GalbraithP@dfo-mpo.gc.ca>]

I'm packaging a new version of xtide and decided to make
/etc/xtide/harmonicspath a conffile.

# cat /var/lib/dpkg/info/xtide.conffiles
/etc/init.d/xttpd
/etc/cron.weekly/xtide
/etc/xtide/harmonicspath

Here's what happens when I try to purge this new package in
slink:

# dpkg --purge xtide
(Reading database ... 58084 files and directories currently installed.)
Removing xtide ...
Stopping Harmonic tide clock and tide predictor server: xttpd.
dpkg - warning: while removing xtide, directory `/etc/xtide' not empty so not removed.
Update-menus: waiting for dpkg to finish(forking to background)
Update-menus: (checking /var/lib/dpkg/lock)
Purging configuration files for xtide ...
Update-menus: waiting for dpkg to finish(forking to background)
Update-menus: (checking /var/lib/dpkg/lock)
mixing# 

Note the warning about /etc/xtide not being empty.  It occurs
_before_ the message "Purging configuration files for xtide ...".
After this operation, I'm left with an empty /etc/xtide/ directory.

I have the same problem pourging the same slink-built package in
potato (I have a compilation problem in potato's g++ and have not
succeeded in building a potato package yet).

I'm using dpkg 1.4.0.35 in slink, and 1.4.1.13 in potato.

Any ideas?  Am I doing something wrong in the packaging?

Peter