여기 나온대로 해 보니 조금 나아진듯 합니다.
적어도 youtube 에서 재생중 끊어지는 현상은 없어진 듯 합니다.
sudo apt-get remove -y --purge flashplugin-nonfree gnash gnash-common mozilla-plugin-gnash swfdec-mozilla libflashsupport nspluginwrapper
sudo rm -f /usr/lib/mozilla/plugins/*flash*
sudo rm -f ~/.mozilla/plugins/*flash*
sudo rm -f /usr/lib/firefox/plugins/*flash*
sudo rm -rfd /usr/lib/nspluginwrapper
sudo apt-get install ia32-libs nspluginwrapper
wget http://download.macromedia.com/pub/labs/flashplayer10/flashplayer10_install_linux_051508.tar.gz
tar zxvf flashplayer10_install_linux_051508.tar.gz
sudo cp install_flash_player_10_linux/libflashplayer.so /usr/lib/mozilla/plugins/
rm -rf ~/install_flash_player_10_linux/
sudo rm -f /usr/lib/mozilla/plugins/*flash*
sudo rm -f ~/.mozilla/plugins/*flash*
sudo rm -f /usr/lib/firefox/plugins/*flash*
sudo rm -rfd /usr/lib/nspluginwrapper
sudo apt-get install ia32-libs nspluginwrapper
wget http://download.macromedia.com/pub/labs/flashplayer10/flashplayer10_install_linux_051508.tar.gz
tar zxvf flashplayer10_install_linux_051508.tar.gz
sudo cp install_flash_player_10_linux/libflashplayer.so /usr/lib/mozilla/plugins/
rm -rf ~/install_flash_player_10_linux/
sudo nspluginwrapper -i /usr/lib/mozilla/plugins/libflashplayer.so
sudo ln -sf /usr/lib/nspluginwrapper/plugins/npwrapper.libflashplayer.so /usr/lib/mozilla/plugins/
sudo ln -sf /usr/lib/nspluginwrapper/plugins/npwrapper.libflashplayer.so /usr/lib/firefox-addons/plugins/
sudo ln -sf /usr/lib/nspluginwrapper/plugins/npwrapper.libflashplayer.so /usr/lib/xulrunner-addons/plugins/
다른 방법이....
여기 에서 64 비트 버전의 리눅스용 Flash Player 를 다운로드 받습니다..