My wife's computer recently started giving her grief. The browser had started to report that "the plugin could not be loaded" on Flash-using sites (ie, Facebook, and most of our 8-year-old daughter's play sites). It is a somewhat elderly machine (AMD Athlon XP 2600+), but it had been running Ubuntu 10.04 LTS (Lynx) nicely for quite some time. I've used Firefox for years, and that was the browser running on that machine too.
I had heard said that Adobe was no longer going to provide Flash for Linux (outside of Chrome), and so I thought I'd try two Flash alternatives: Lightspark and Gnash. The very nice Flash-Aid Firefox plugin made this attempt very straightfoward. However, although the plugins loaded and reported their version numbers to Adobe's test site (http://www.adobe.com/software/flash/about), Facebook said I needed to upgrade the plugin. So the latest Adobe plugin didn't work, and the alternatives worked, but they were too far back.
Let's try a new browser. I read that Google Chrome had "integrated" Flash support, so I thought I could just download and go. So I downloaded Chrome, but the flash plugin still would not run.
Sigh. I suppose it's time to upgrade the OS. I had gotten out of the habit of upgrading that particular machine because,
1. If it ain't broke don't fix it,
2. I had had a pretty messy upgrade experience once with that particular machine.
3. And now that I was several revs back, I'd have to step through each new version to get up-to-date.
So after each version upgrade, I'd try Firefox and Chrome (and Chromium too) to see whether Flash sites would load. 10.10 -- Nope. 11.04 -- Nope. 11.10 -- Nope.
I started to wonder whether I had some kind of incompatibility with my card (an old nVidia GeForce 5200 [I told you this machine was old]) and Flash. I saw references to weird behavior (like the Smurf effect), but none of the fixes for those issues addressed the problem I was having.
In one of the debian forums, there's a thread titled "New Bug: Google Chrome - Couldn't initliaze plug-in" The originator was describing something very similar to what I'm experiencing. The hero of that post asked whether his CPU supported SSE2 instructions. Sure enough
cat /proc/cpuinfo | grep flags
implied that my CPU doesn't. The poster also said he thought the 126.96.36.199 didn't have the problem which was affecting the latest version.
I downloaded the archive, pulled out libflashplayer.so, and put it into /opt/google/chrome/plugins.
That solved the problem!