I am experiencing the same error. I think this is related to https://bugs.launchpad.net/ubuntu/+source/firefox-3.5/+bug/397211 as it varies from site to site.
Example: http://www.adobe.com/software/flash/about/ detects flash A-OK but Vanguard's website doesn't until I change my user-agent to a "Firefox/3.5" variant from the "Shiretoko/3.5" default. Example public Vanguard link: https://personal.vanguard.com/us/accounttypes/advice/ATSAdviceOnAssetMgmtContent.jsp FYI: flashplugin-nonfree: Installed: 10.0.22.87ubuntu2 Candidate: 10.0.22.87ubuntu2 Version table: *** 10.0.22.87ubuntu2 0 500 http://mirrors.us.kernel.org jaunty/multiverse Packages 100 /var/lib/dpkg/status swfdec-mozilla: Installed: (none) Candidate: 0.8.2-1ubuntu1 Version table: 0.8.2-1ubuntu1 0 500 http://mirrors.us.kernel.org jaunty/universe Packages mozilla-plugin-gnash: Installed: (none) Candidate: 0.8.5-0ubuntu1 Version table: 0.8.5-0ubuntu1 0 500 http://mirrors.us.kernel.org jaunty/universe Packages -- Firefox 3.5 does not detect flash player https://bugs.launchpad.net/bugs/394467 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs