Urk! apt wants to uninstall my entire system!

[Gavin Hamill <gdh@acentral.co.uk>]

Hello :)

I did an apt-get update today on my alpha 'unstable' system and nearly
required new trousers this morning when I almost pressed 'Y' to this
little lot...

macha:/home/gdh/# apt-get dist-upgrade
Reading Package Lists... Done
Building Dependency Tree... Done
Calculating Upgrade... Done
The following packages will be REMOVED:
  adduser analog apache apache-common autoconf automake build-essential
courier-imap cvs-buildpackage
  debhelper debiandoc-sgml debmake devscripts dh-make dlint docbook
docbook-stylesheets docbook-to-man
  docbook-xml docbook2man docbook2texi dpkg-dev dpkg-ftp dpkg-perl dupload
flexml horde imp jade
  kernel-package libapache-mod-ssl libdate-manip-perl libdbd-mysql-perl
libdbi-perl libdevel-symdump-perl
  libdigest-md5-perl libhtml-parser-perl libhtml-tagset-perl
libi18n-langtags-perl libmime-base64-perl
  libmldbm-perl libnet-perl libsgmls-perl libtext-format-perl liburi-perl
libwww-perl libxml-dom-perl
  libxml-dumper-perl libxml-generator-perl libxml-grove-perl
libxml-node-perl libxml-parser-perl
  libxml-perl libxml-rss-perl libxml-twig-perl libxml-writer-perl lintian
listar-cgi mysql-client
  mysql-server openssl perl-5.004 perl-5.004-base perl-5.005 perl-5.6 php4
php4-imap php4-mysql qmail-src
  sgml-base sgml-data sgmlspl sgmltools-2 sp task-c++-dev task-c-dev
task-debian-devel task-devel-common
  task-dns-server ucspi-tcp-src xaw-wrappers xaw3dg xbel xbel-utils
The following NEW packages will be installed:
  libcap1 sfio1999
20 packages upgraded, 2 newly installed, 84 to remove and 0 not upgraded.
Need to get 41.5MB of archives. After unpacking 80.9MB will be freed.
Do you want to continue? [Y/n] 

I've had a fair amount of truck with apt and package problems before, 
but I have no idea where to start looking to fix this one?

I'm open to suggestions! :)

Kind regards, 

Gavin.