Caveat in flash player: it fails in firefox after start (linux-f10-flashplugin-11.2r202.310)

[Yuri]

I have one machine on which flash fails to work when firefox browser is 
just started and some youtube video is opened. It displays this message 
in white and blue colors:
*
**/The Adobe Flash Player or an HTML5 supported browser is required for 
video playback.//
//Get the latest Flash Player//
//Learn more about upgrading to an HTML5 browser/*

It looks like the flash itself decides it has the wrong version and asks 
to update.
Reloading the page doesn't help. However, killing all processes with the 
name npviewer.bin and then reloading the page helps.

On the other machines I also occasionally observed the similar but not 
the same problem when browser says that plugin isn't available after 
brower is launched. But later, after refresh, it works. And this looks 
like the different issue.

The procedure from handbook was followed to the word. There are no stray 
files with the names libflash*so* anywhere.
So I had to create a special hotkey to 'killall npviewer.bin' as a 
workaround.

Anybody knows why this happens and what is the better fix? I know 
flashplugin itself and nspluginwrapper are crappy pieces of software, 
but so many sites heavily rely on flash anyway.

Yuri