Probably the same problem here. Attempt to install using 126.96.36.199 obtained today at http://get.adobe.com/flashplayer/ fails as previous Flash Player 13 Installers have failed ("Error: Unable to proceed with installation" message during the installation attempt). I also removed previous Flash Player versions FWIW using the official uninstaller. Mac OS X 10.9.2 here. I was hopeful that today's release would fix this problem for me. This is rather annoying.