Comment 2 for bug 947639

The error here is:

dpkg: error processing libudev0 (--configure):
 libudev0:amd64 175-0ubuntu5 cannot be configured because libudev0:i386 is in a different version (175-0ubuntu6)
dpkg: error processing libudev0:i386 (--configure):
 libudev0:i386 175-0ubuntu6 cannot be configured because libudev0:amd64 is in a different version (175-0ubuntu5)
[...]
dpkg: error processing libgudev-1.0-0 (--configure):
 libgudev-1.0-0:amd64 1:175-0ubuntu5 cannot be configured because libgudev-1.0-0:i386 is in a different version (1:175-0ubuntu6)
dpkg: error processing libgudev-1.0-0:i386 (--configure):
 libgudev-1.0-0:i386 1:175-0ubuntu6 cannot be configured because libgudev-1.0-0:amd64 is in a different version (1:175-0ubuntu5)

However, this is part of a secondary run of apt attempting to clean up as many packages as possible following an earlier error; that earlier error is the root problem:

Selecting previously unselected package libvisual-0.4-plugins:i386.
dpkg: error processing /var/cache/apt/archives/libvisual-0.4-plugins_0.4.0.dfsg.1-5_i386.deb (--unpack):
 libvisual-0.4-plugins:i386 0.4.0.dfsg.1-5 (Multi-Arch: no) is not co-installable with libvisual-0.4-plugins:amd64 0.4.0.dfsg.1-5 (Multi-Arch: no) which is currently installed

Surprisingly, although libvisual-0.4-plugins installs to the multiarch path, it is not marked as Multi-Arch: same, resulting in this error when dpkg tries to unpack the package for both architectures.

What's not clear at all is why apt would try to do this when the package is not marked M-A: same.