Have you tried other computers to check such a possibility..
Hope this helps.
I am having problems getting Adobe Flash player to work on certain websites. It won't play the game highlights videos in NHL.com, but will play the Game of the Day on the home page! Also, videos in Ninemsn.com will not play, but I have no problems using Youtube or many other sites.
I have an Acer laptop running Vista Premium, with Firefox 3. I have wireless internet with a min 500 - 1000 kbps. I have uninstalled (using Adobe uninstaller) and reinstalled Flash player many times to no avail.