With this version, in Opera the videos are mute, and in Firefox they're blank. Only when installing the earlier stable version the videos work properly. In Chrome this version also works.
We're definitely not seeing that on our end. We'd like to investigate further, but would need more specifics about your configuration and the version of Flash Player you're using.
We need enough information to successfully reproduce the problem on our end. Step by step instructions, links to problematic content, and detailed information about your configuration are all extremely helpful in this regard.
Please update to the latest preview release (11.3 Beta 2 - 11.3.300.231), and see if the issue persists.
If you're still running into trouble, please file a bug here: https://bugbase.adobe.com/, and update this thread (I'll keep an eye on it).
It would be extremely helpful to know what OS and Browser versions you're running.
Also, please double-check that Flash has successfully installed, by going here: http://helpx.adobe.com/flash-player/kb/find-version-flash-player.html
Confirm that both the animation is playing, and that the version number displayed matches the version number you expect. In this case, 11.3.300.231.
It seems that I've made an error for which I apologize. This newest Beta version indeed works properly with international videos (YouTube &c.). It only seems not to work with the local videos ( http://areena-beta.yle.fi/ng/areena/tv ) of the Finnish Broadcasting Company (YLE) that I frequently watch (with Beta, these videos are vithout sound). Probably the company is not yet up-to-date with the Flash Beta. This with Opera 11.62 (build 1347). OS is Win Vista Home Premium (32.bit). However, something is definitely wrong with Firefox (v 12.0): the list of the browser's plugins shows Flash Beta (11.3.300.231) as being installed, yet the double-check page you mentioned is completely blank (no Flash video, no information of the version number), and the videos elsewhere are black with an error message.
I can also confirm with the latest beta preview release and also the previous beta of 11.3 works on that website, in firefox v11, opera 11.62 and ie9, there is however a problem i posted about 100% load on the cpu in this website, dopehood.com, give a few seconds then all of a sudden my cpu spikes and stays at 100% untill i leave, i really need someone else to try this website, i have tried 11.2 and 11.3 and doesnt make any difference, im not downgrading 11.1 to find out if it is those versions or if its just that website, please, someone try, have a look in task manager when the page as fully loaded.2 weelks ago i had 11.1 installed and i never had 100% load, so if its happenening now with 11.1 then it is indeed the website. Firefox 12 is abeta so you cant include that as that is still in a testing phase also.