Download the .bin file to your PC. Then put a static IP address on the PC your trying to send the FW to, say 192.168.0.100, then open the browser to the DAPs web page and if your seeing the Recovery Mode screen, It should have a button to locate the .bin file to send. See if it will accept the file.
If this doesn't work then you'll need to call DLink support and RMA the unit.