you can try a different browser...
these will help you...
1. Use Opera browser, it will load faster and smoother, and re-install latest flash (the correct way)
get the latest flash player, and install it.. make sure all the browsers are NOT running during installation... this is the right way to install the flash player.
2. It could be due to slow connection or high traffic.
Try watching it during off peak hours, the video will be smoother.
Or you could watch it offline smoothly... try using 'zillatube' .
It works well - Just google search "zillatube" to get it.