installing open source flash plugin gplflash - at least it works in 64bit mode

download from http://gplflash.sf.net/

sudo apt-get install libmad0-dev

tar -jxvf gplflash-0.4.13.tar.bz2

cd gplflash-0.4.13

./configure --prefix=/opt/gplflash

make ; sudo make install

cd /opt/gplflash/lib/mozilla/plugins

cp libnpflash.so /usr/lib/mozilla-firefox/plugins/