package flashplugin-installer (not installed) failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[Scott Sweeny]

During an upgrade to Oneiric the flashplugin-installer package failed to install properly. The flash plugin is downloaded and installed but then this error message appears:

Download done.
Flash Plugin installed.
nspluginwrapper: no appropriate viewer found for /usr/lib/flashplugin-installer/libflashplayer.so
dpkg: error processing flashplugin-installer (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 flashplugin-installer

ProblemType: Package
DistroRelease: Ubuntu 11.10
Package: flashplugin-installer (not installed)
ProcVersionSignature: Ubuntu 3.0.0-9.12-generic 3.0.3
Uname: Linux 3.0.0-9-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Sun Aug 21 01:56:18 2011
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1)
SourcePackage: flashplugin-nonfree
Title: package flashplugin-installer (not installed) failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to oneiric on 2011-08-21 (1 days ago)