Hi,
Just wanted to say a big thankyou for this useful post/solution, and relate my experiences for anyone else who has the same problem.
All over the net there's people saying to just do
# apt-get install flashplugin-nonfree
to install the flash plugin for iceweasel/firefox/whatever, but whenever I tried that I got the error: "Package flashplugin-nonfree has no installation candidate". I eventually tracked this down to the fact that I'm trying to install this on an amd64 installation. As a result of the error, I couldn't even install 32 bit flash (via apt anyway) and use the nspluginwrapper that so many people suggest out there. I hope that more people find this post and can follow the same simple steps I did:
# vim /etc/apt/sources.list
changed
to
# apt-get update
# apt-get install flashplugin-nonfree
Tested that quickly and it works perfectly for flash toons, games and youtube videos.
I didn't really get the apt-pinning stuff from that guide (sorry, but I'm still pretty new to linux), so just ran
# vim /etc/apt/sources.list
(again) and changed those two lines back to what they were before. I guess it'd be nice to be able to say "use the Sid repo for just the flashplugin-nonfree package, and use stable (or whatever) for everything else." The apt-pinning stuff looked like id could do that, but as I say, I didn't quite get the specifics of how to achieve this.
Anyway, I've rambled on long enough for my first ever post on this forum, but hopefully all those search-engine-friendly relevant words will help people find this :-).
Once again, thanks for the tip, and long may Linux grow.