ubuntu-desktop removal blacklist error message uninformative

[DAP]

Binary package hint: update-manager

I get an error when I try and upgrade my Ubuntu 9.10 system indicating that ubuntu-desktop is in the removal blacklist.
The likely cause is an unsupported package installed, but there is no indication of which package put ubuntu-desktop on the removal black list, nor any suggestion of how to find out.
I run mythTV on this system, and am running the daily builds, this may be the cause, or it may be one of the other packages I have installed.
Since there is a black list, I would hope there is a record somewhere of what package put what on the blacklist.
So if there is a log file for the black list, the bug is that the error message did not say what it was called or where to look for it.
If there is no log file, the lack of a log file is the bug.

ProblemType: Bug
Architecture: amd64
CheckboxSubmission: 4f08ac62e89ad166a1e0b05f95495253
CheckboxSystem: fd6c484c0b5d20a2f1cd036ef0f63975
Date: Fri Apr 30 06:12:39 2010
DistroRelease: Ubuntu 9.10
NonfreeKernelModules: fglrx
Package: update-manager 1:0.126.9
PackageArchitecture: all
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-21.59-generic
SourcePackage: update-manager
Uname: Linux 2.6.31-21-generic x86_64
XsessionErrors:
 (gnome-settings-daemon:3338): GLib-CRITICAL **: g_propagate_error: assertion `src != NULL' failed
 (polkit-gnome-authentication-agent-1:3412): GLib-CRITICAL **: g_once_init_leave: assertion `initialization_value != 0' failed
 (nautilus:3392): Eel-CRITICAL **: eel_preferences_get_boolean: assertion `preferences_is_initialized ()' failed
 (gnome-panel:3375): Gtk-WARNING **: gtk_widget_size_allocate(): attempt to allocate widget with width -3 and height 24
 (gnome-panel:3375): Gdk-WARNING **: /build/buildd/gtk+2.0-2.18.3/gdk/x11/gdkdrawable-x11.c:952 drawable is not a pixmap or window

[Jean-Baptiste Lallement (jibel)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 571743, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.