Another working solution: rollback to 11.1

After a long wrestling with this problem on several computers, I finally came over by the solution from hikerKS here:
http://forums.adobe.com/message/4469009

To check the status of your Flash in any instant and to remove the current version, you can use this page:
http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html