How to install flash for firefox in ubuntu 12.04?
step1. download tar.gz package from adobe flash download site.
step2. unzip tar.gz package.
step3. copy libflashplayer.so library to /usr/lib/firefox/plugins : sudo cp libflashplayer.so /usr/lib/firefox/plugins
step4. copy usr directory files to /usr :sudo cp -r usr/* /usr
reboot firefox. complete install process... enjoy...
From: http://blog.csdn.net/wchinaw/article/details/8240894