Comment 10 for bug 877681

ok, so the culprit is shared-mime-info; for some reason apt calculated that it would be better to install the i386 version of this package instead of the amd64 one, despite the package being Multi-Arch: foreign (meaning any architecture will suffice, but the native architecture is preferred). And shared-mime-info has to have a matching version of libxml2, which has not been converted yet for multiarch, resulting in the amd64 version being kicked out.

If you had already had the amd64 shared-mime-info installed before installing ia32-libs, this probably would not have occurred.

Assigning this bug to apt, which should be more aggressive about preferring the amd64 package versions.