unable to open movies in certain sites using Firefox 4, no problem with former versions
As a almost daily visitor of the site Bigfun.be I got a crash every time I wanted to open a movie, since I started using Firefox 4. After some automatic updates, the crashes disappeared. But it's still unable to open movie files. There is a message which says that the file is being loaded, but it isn't. I've contacted the webmaster, he knows about the problem and suggested me to uninstall the version 4 and to go back to the 3.6 version.
Wšě wotmołwy (3)
I went to that site and played a couple of movies without a problem. Cat & Budgie and Horse on the back seat of a car...lol.
Have a look at your firewall logs. Is the firewall blocking plugin_container.exe by any chance? That utility is part of Firefox and acts like a kind of sandbox to isolate plugins which crash without crashing the whole browser. But it does need Internet access. Generally speaking, what often happens is the firewall throws up an alert to which the user doesn't respond. So the firewall 'assumes' it's a threat and blocks it.
Can you go to this site: http://www.liveleak.com/ and click on any video. Is the player visible even if it doesn't play?
Since the new upgrades I have not been able to play embedded movies or clips. For example, today 4/28/11, there was a FF update. Part of the tutorial, step 2 Know Your Browser, I was not able to open and run this. I have other issues, but this is enough for now.
Can you play videos on youtube.com ? I've noticed that with other users who had similar problems to yourself, they were able to play videos elsewhere after playing one on youtube. Worth a try anyway.
Did your firewall logs reveal anything?
If the problem persists, try running Firefox in Diagnose Firefox issues using Troubleshoot Mode. If it functions properly in that configuration, then one of your add-ons is the culprit.