Comment 9 for bug 900512

Steve, this isn't about uninstalling stuff. It's about not being able to install ia32-libs.

Why invalid when it's a real problem?

$ sudo apt-get install ia32-libs-multiarch
[...]
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 ia32-libs-multiarch:i386 : Depends: ibus-gtk:i386 but it is not going to be installed
                            Depends: libcanberra-gtk-module:i386 but it is not going to be installed
                            Depends: libcap2:i386 but it is not going to be installed
                            Depends: libgphoto2-2:i386 but it is not going to be installed
                            Depends: libgphoto2-port0:i386 but it is not going to be installed
                            Depends: libsane:i386 but it is not going to be installed
                            Depends: libpam-winbind:i386 but it is not going to be installed