Hopefully my last message about it all.
> Bad news:
> no sound from www.youtube.com
> 
> you need libflashsupport.so to get OSS sound support
> (NetBSD doesn't have ALSA, it only knows OSS)
> https://svn.revolutionlinux.com/MILLE/RELEASE/mille-xterm/Mandriva/2006/devel/i586/libflashsupport-1.0-2098.i586.rpm
> is where you get libflashsupport.so
> extract the rpm and
> cp libflashsupport.so /usr/pkg/lib/netscape/plugins

And this was where I went wrong
Tonight I did
cp libflashsupport.so /emul/linux/usr/lib

And a working youtube with sound :-)

The audio still isn't completely in sync with the video,
but it is a million miles better than crashing.

Many thanks again to Geert Hendrickx for the hint about nspluginwrapper.

Onno