Also got this problem (Kubuntu 11.04, 64 bits) today after desinstalling and reinstalling nspluginwrapper to update flashplayer, following this: http://doc.ubuntu-fr.org/flashplayer
deleting all the files in /usr/lib64/mozilla/plugins and reconfigure dkpg solved the problem too:
cd /usr/lib64/mozilla/plugins/
sudo rm *
sudo dpkg --configure -a
Also got this problem (Kubuntu 11.04, 64 bits) today after desinstalling and reinstalling nspluginwrapper to update flashplayer, following this: http:// doc.ubuntu- fr.org/ flashplayer
deleting all the files in /usr/lib64/ mozilla/ plugins and reconfigure dkpg solved the problem too:
cd /usr/lib64/ mozilla/ plugins/
sudo rm *
sudo dpkg --configure -a