Ok, I can confirm I get the same problem on that page - but I believe it to be more likely a problem with Flash than a problem with Firefox, so I shall mark it as such.
** Package changed: firefox (Ubuntu) => adobe-flashplugin (Ubuntu) ** Changed in: adobe-flashplugin (Ubuntu) Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to firefox in Ubuntu. https://bugs.launchpad.net/bugs/831598 Title: Some videos won't play. All I get is a blank black screen. Status in “adobe-flashplugin” package in Ubuntu: Confirmed Bug description: I have had this problem with several videos. The links take me to the video's, but there is nothing but a blank black screen, and no way to play to video. ProblemType: Bug DistroRelease: Ubuntu 11.04 Package: firefox 6.0+build1+nobinonly-0ubuntu0.11.04.1 ProcVersionSignature: Ubuntu 2.6.38-11.48-generic 2.6.38.8 Uname: Linux 2.6.38-11-generic x86_64 NonfreeKernelModules: nvidia Architecture: amd64 Date: Mon Aug 22 15:59:01 2011 FirefoxPackages: firefox 6.0+build1+nobinonly-0ubuntu0.11.04.1 flashplugin-installer 10.3.183.4ubuntu0.11.04.1 adobe-flashplugin N/A icedtea-plugin 1.1.1-0ubuntu1~11.04.1 InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1) ProcEnviron: LANGUAGE=en_US:en LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: firefox UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/adobe-flashplugin/+bug/831598/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp