Flash Plugin fails to install

Binary package hint: flashplugin-nonfree

After upgrading to Ubuntu Hardy (development version) the flashplugin-nonfree package is reported broken. Attempts to repair it result in the following:

Setting up package flashplugin-nonfree (9.0.115.0ubuntu3) ...
Installing from local file /var/cache/flashplugin-nonfree/install_flash_player_9_linux.tar.gz
Flash Plugin installed.
/usr/lib/nspluginwrapper/i386/linux/npviewer.bin: error while loading shared libraries: libselinux.so.1: cannot open shared object file: No such file or directory
nspluginwrapper: no appropriate viewer found for /usr/lib/flashplugin-nonfree/libflashplayer.so
dpkg: couldn't manage flashplugin-nonfree (--configure):
 subprocess post-installation script returned error code 1
The following packages failed to be managed:
 flashplugin-nonfree

And, of course, no flash is available in Firefox.