Hi,
As you are using VisualDSP++ 5.1 the drivers you are using are the latest 64-bit drivers.
Can you check the drivers folder at the following location and let me know which files appear:
C:\Program Files (x86)\Analog Devices\VisualDSP 5.x\Blackfin\Examples\usb\host\windows\drivers\
The file that you require in order to install the device is 'Bulkadi64.sys'. If you do not have this file please contact private support, quoting this thread, and we can provide you with the required drivers. You can conatct private support using the following email address: processors.tools.support@analog.com.
Regards,
Colin