I am using the HTML5 player. I removed the Flash player from my system, and when I click on the "Switch to Flash player" link, I just get a black rectangle. I have to click on "Switch to HTML5 player" to get to something that works. Not to say that this isn't the issue you're seeing, but it isn't a universal issue for some reason.

Oh interesting, just to make sure I'm following everything, when you're using the HTML5 player embedded videos on other sites work for you. Correct?

Well, this one did: [url]http://www.youtube.com/watch?v=HeAcZ44gGKs[/url]

Had to turn on the HTML5 trial on youtube, otherwise I just got a black rectangle. When I turned it off, I went back to the black rectangle.

Other sites I should try?

Oh, we may be talking about different things here. There is a bug that is specific to pages with the embedded vimeo player and html5 is enabled for the user. It doesn't have anything to do with flash being installed or not, just that the html5 player is enabled and you're trying to view a vimeo video embedded on a third-party site.

Same for me, video will not play.

They do work if I "Switch to Flash player," I'd not noticed that choice. Of course, I'd prefer to avoid Flash if possible but at least now i'll be able to see the clips on the short term.

Without any known changes, the vimeo clips now fail for me with the html5 player, too.

I set OW to spoof vimeo by saying the browser was Safari 4.0. With that setting the flash version works just fine.

I am also having this issue. Switching to Flash Player works fine. It did not surface until I upgraded to this current build.