I think this has been around along time, I just haven't used KDE as a DE, or Konq as a browser.
The plugin does a signal 11 on flash sites with Konqueror. Can Konq do flash ?
nspluginviewer is a dependancy of kdebase & kdecore,
Are you on 3.5.12 or the nightly builds?
The reason I ask is that a number of fixes for nspluginviewer have been committed to SVN since the release of 3.5.12.
Thanks!
Tim