kernel upgrade fails when multiarch enabled

[Julian Taylor]

Binary package hint: nvidia-common

when upgrading the kernel 2.6.38-37 /etc/kernel/header_postinst.d/nvidia-common fails:

Setting up linux-headers-2.6.38-7-generic (2.6.38-7.39) ...
Examining /etc/kernel/header_postinst.d.
run-parts: executing /etc/kernel/header_postinst.d/dkms 2.6.38-7-generic /boot/vmlinuz-2.6.38-7-generic
 * dkms: running auto installation service for kernel 2.6.38-7-generic
 * virtualbox-ose (4.0.4)... [ OK ]
 * nvidia-current (270.30)... [ OK ]
run-parts: executing /etc/kernel/header_postinst.d/nvidia-common 2.6.38-7-generic /boot/vmlinuz-2.6.38-7-generic
Traceback (most recent call last):
  File "/usr/bin/nvidia-detector", line 8, in <module>
    a = NvidiaDetection(printonly=True, verbose=False)
  File "/usr/lib/python2.7/dist-packages/NvidiaDetector/nvidiadetector.py", line 68, in __init__
    self.getData()
  File "/usr/lib/python2.7/dist-packages/NvidiaDetector/nvidiadetector.py", line 134, in getData
    for package in apt.Cache():
  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 173, in __iter__
    yield self[pkgname]
  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 158, in __getitem__
    pkg = self._weakref[key] = Package(self, self._cache[key])
KeyError: 'ardour-i686'
run-parts: /etc/kernel/header_postinst.d/nvidia-common exited with return code 1
Failed to process /etc/kernel/header_postinst.d at /var/lib/dpkg/info/linux-headers-2.6.38-7-generic.postinst line 110.
dpkg: error processing linux-headers-2.6.38-7-generic (--configure):
 subprocess installed post-installation script returned error exit status 2
Setting up libncurses5-dev (5.7+20101128-1) ...
Setting up libreadline6-dev (6.2-0ubuntu1) ...
Errors were encountered while processing:
 linux-image-2.6.38-7-generic
 linux-headers-2.6.38-7-generic
E: Sub-process /usr/bin/dpkg returned an error code (1)

I have enabled multiarch by adding APT::Architectures { "amd64"; "i386"; } to apt.conf and foreign-architecture i386 to dpkg.cfg

When I remove those entries the upgrade of the kernel succeeds.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: nvidia-common 0.2.28
ProcVersionSignature: Ubuntu 2.6.38-7.38-generic 2.6.38
Uname: Linux 2.6.38-7-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Sat Mar 26 12:39:09 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha amd64 (20110318)
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: nvidia-common
UpgradeStatus: No upgrade log present (probably fresh install)