Most of the time when you cant get these boards running it is related to the eval code being developed on either 32bit or Windows XP, not 64bit. I had a heck of a time getting a 9959 board running on anything other than windows XP. No logic behind it, just wouldn't run until I used XP.
The odds of the 9959 chip being counterfeit are almost zero. Maybe the cypress chip if it has one but the 9959s unlikely. Try XP and go from there. The other issue generally is that you have to be careful to use the wall wart they supply or the correct power. Don't assume 5v or 12v or whatever. I blew a board once using 12V when 5v was spec'ed.
Jerry
There are different kind of boards, official from Analog has DDS AD9959 + supplementary uCPU , so DDS synthesizer could be interfaced and configured from PC, over USB interface. uCPU serves as an USB->to->SPI bridge.
This is what, probably, you mean.
But if you click a link from first message, there would be a picture of the board I've got, cheapest version w/o any bridges. Consequently, there is no USB, just raw SPI bus pin header.
I'm still waiting a replacement, "ticket" is open on ebay. I'd post updates when I received one.