NI offers a workaround. You can use the 32bit version of the latest Traktor version. Details on
http://www.native-instruments.com/en/support/knowledge-base/show/3886/my-audio-interface-is-not-recognized-after-installing-traktor-2.8.0-windows/
The latest information I found about it from Pioneer is 5 days ago. See thread
http://forums.pioneerdj.com/hc/communities/public/questions/203083209-DDJ-SZ-64-bit-ASIO-drivers-?page=1#answer-203716099