apt-get problem when upgrading from slink/corel to potato

[Sven LUTHER <luther@dpt-info.u-strasbg.fr>]

any idea of what is the cause of the following problem ? from the look of it
it is an upgrade from corel-linux to potato (user claims from slink to
potato).

mooby:~# apt-get dist-upgrade
Reading Package Lists... Done Building Dependency Tree... Done Calculating
Upgrade... Done The following packages will be REMOVED:
  timezones secure-su lynx libpam0g-util lesstifg-dbg lesstifg-dev
kde-corel
  libreadlineg2-dbg libreadlineg2-dev libstdc++2.9-dev newt0.25 ppp-pam
  timidity The following NEW packages will be installed:
  libpopt0 libncurses5 traceroute perl-5.004-base libwrap0 libpam-modules
  xchat-common perl-5.004 libgtk1.2 ruptime libglib1.2 libsane
libpam-runtime
  rusers lockfile-progs libpcre2 mc-common xpilot-server tcpd rdate
cfingerd
  perl-5.004-doc python-base tftp finger libstdc++2.10 icmpinfo freetype2
rwho
  bootpc libwmf0 rdist ftp rwall midentd rwhod rcs libasound0.4 fping
libbz2
  libaudiofile0 libgsm1 gettext-base tcl8.2 alsa-base tk8.2 rsh-client
  libstdc++2.10-dev libnewt0 libreadline4 liblockfile1 The following
packages have been kept back
  gnuplot ddd cvs efax kbd eterm exim 
319 packages upgraded, 51 newly
installed, 13 to remove and 7 not upgraded. Need to get 0B/114MB of
archives. After unpacking 50.4MB will be freed. Do you want to continue?
[Y/n] y
E: Internal Error, Couldn't configure a pre-depend

Any help will be appreciated.

Friendly,

Sven LUTHER