Problem with YouTube videos

I am using Safari, which is updated to the latest version.I am also running the latest version of Lion.

In the last few months a very annoying problem started happening to me regarding YouTube videos. After a minute or so from the moment the video starts, the video pauses and a spinning dotted circle appears. I can wait for hours but the video does not restart. It is not buffering.

I have a fast internet connection. What is more confusing is the fact that the problem does not apper in all videos, only 60% of them.

In an effort to sort this problem out, I have recently uninstalled Flash player and installed it again from Adobe's web site.

What could be the problem? Any suggestions? Your help will be most appreciated.

Regards and thanx in advance. - Andreas