I’ve got some problems with adobe flashplayer on my linux box with debian squeeze. Youtube videos doesn’t play and only shows a black window without any other action. Google tells me to get an older version of the flashplayer from adobes site and install it. But there is no debian package and I would like to have a clean installation with the debian package management system. Here is my way to downgrade flashplayer from Version 11 to Version 10.3.

In my /etc/apt/sources.list I have the entry to the debian-multimedia repository:

deb http://www.deb-multimedia.org squeeze main non-free

First I clean up the system from any flashplayer:

$ sudo aptitude purge flashplayer-mozilla flashplugin-nonfree flashplugin-nonfree-extrasound gnash

$ sudo find / -xdev -name libflashplayer.so
and delete any laying around libflashplayer.so

Get the older version of the flashplayer you want from:
http://ubuntu.bio.lmu.de/debian-multimedia/pool/non-free/f/
I used flashplayer-mozilla_10.3.183.7-0.0_i386.deb

Then install it:

$ sudo dpkg -i flashplayer-mozilla_10.3.183.7-0.0_i386.deb

To suppress any updates on this package add tihis entry to your /etc/apt/preferences:

Package: flashplayer-mozilla
Pin: version *
Pin-Priority: -1

That’s it.