I have ubuntu 12.04 64bit using Google Chrome. I had chromium from the app center then today amazon prime video stopped working. It told me to update Flash. So I uninstalled chromium and installed Google Chrome. Didn't work. Then I downloaded flash for ubuntu via apt. That one gave me a "flash version isn't supported" message.
The flash version was 11.
Now I tried http://apt.ubuntu.com/p/flashplugin-installer
It worked, but right in the middle of the video, it popped the error message again.
Sorry we are unable to stream this video. This is likely because your Flash Player needs to be updated.
So I don't know what happened.