Sometimes Flash updates OK, sometimes it breaks with an error "Actionlist not found".
That's probably because I'm tucked away behind a web proxy, or maye Sophos sticks its oar in.
If the 990k updater (like install_flashplayer11x32_gdrd_aih.exe) fails, uninstall completely, then get the whole 17MB installer install_flash_player.exe from
( http://download.macromedia.com/pub/flashplayer/current/support/install_flash_player.exe )
That solves it. You're welcome, Future Self.