flash player required for watching wpmu videos

HI - i have a post which uses the videos that have now been registered, and trying them myself i see i need to have flash player installed, which i did, and yet the video code apparently is not recognizing my flash player (11) install. i am using firefox on a 64 bit W7 OS. Is there something in my browser that would cause the flash not to be recognized, or is it something else?
see which at
please advise...
thanks in advance