Well, as Firefox says: -Well, this is embarrassing, also happens to Opera 10 with Flash, Its known if its a server-side problem related to YouTube, or if there is some kind of Bug in Opera 10.
Obviously, the browser version is the latest and also flash, so no doubt due to a YouTube failure, when only a few hours ago we could see it without problems.
After a quick search on Twitter (1, 2, 3, 4, etc …) actually confirms the suspicion, so searching on the internet I found a userscript that seems to fix it.
Here you can see a proof of this is clearly a YouTube programming problems.
To install it, we downloaded from this site.
In Opera, we go to the Youtube´s site, we right click it and select “Edit site options”, we’re going to the Options tab (maybe something like Programming). Click “Choose” and show it the folder where we saved that userscript.