Comment 17 for bug 16502

Fixed this by cleaning up my ~/.mozilla directory. It contained some stale files from older plugin installations which firefox did not use. (After installation of package flashplugin-nonfree firefox used the plugins in /usr/lib/flashplugin-nonfree instead.)

Actually I didn't trace which file was the real cause of the problem but the following steps fixed it:

  aptitude install flashplugin-nonfree konqueror-nsplugins
  cd ~/.mozilla
  rm pluginreg.dat plugins/*
  cd plugins/
  ln -s /usr/lib/flashplugin-nonfree/libflashplayer.so .

(You might want to make backups of the files before removing them.)

I guess that it's possible to make konqueror look into the same directories as firefox. Perhaps it's possible to implement a general fix in the nspluginviewer package in this way.