I am on 11.10 64bit and I have installed flash from http://get.adobe.com/flashplayer/otherversions/.
I had downloaded
install_flash_player_11_linux.x86_64.tar.gz and moved
I also have OSS installed because alsa does not work for me. I generally follow steps mentioned at https://help.ubuntu.com/community/OpenSound and everything works fine.
But for 11.10, flash has no sound. I am not sure if that is OSS problem.