Adobe dropped support of processors without SSE2 on Linux (you can check with "grep ^flags /proc/cpuinfo" the letters "sse2" should be in the list) in an early point release of Flashplayer 11. The player will install, but then crashes when it is invoked. This mostly affects older 32bit AMD processors.
AND don't get the flashplugin 11 but older like 10. But chromium, iron, chrome don't like that and says "the plugin is obsolete".
The parameters to start those browsers with obsolete flashplugin don't work..
So, OPERA is a great browser with a flashplugin 10