I too have been struggling with trying to get the drs4 (507) to work on my windows machine and I found it to be a problem with the libusb library. My solution is as follows and has worked on multiple PC's. I ran this solution after I first plugged in the drs4 and installed 507.
Go to http://zadig.akeo.ie/ and install the corresponding software.
After that, you will need to plug in the DRS4 to your computer. From there go to ‘Options’, and select ‘List all Devices’.
Finally, choose the DRS4 evaluation board from the list and press install driver and let it run. You should be fine after that.