I'm running Windows XP (SP3) - 32bit - and my browser is the latest version of Firefox. When I save the latest Flash Player update (11.7.700.202) and click to install it, I keep getting the same error message and then the file disappears. The only suggestion I can find on-line is to disable one's antivirus program. In my case that's Norton Internet Security, and I've tried that -- as well as disabling the firewall. No luck. I've also tried shutting down Firefox before installing. Finally, I've tried downloading the Adobe installer package, but that produces the error message "...could not be opened."
Thanks! I had tried downloading the installer and it refused to load. This time it worked.