As reported from Adobe
The Flash Player 10.1 64-bit Linux beta is closed. We remain committed to delivering 64-bit support in a future release of Flash Player. No further information is available at this time. Please feel free to continue your discussions on the Flash Player 10.1 desktop forums.
However, all is not lost! there are still 2 servers you can still download the last version from until support starts up (again?) in the future…
Adobe Flash Plugin for Linux x86_64 Server 1
Adobe Flash Plugin for Linux x86_64 Server 2 (courtesy of )