More information: https://www.reddit.com/r/AMDHelp/comments/3xixvs/unable_to_install_drivers_for_r9_390_8g/
Have you tried installing the Crimson Edition 15.12 driver? If not, you can download the latest driver here: Desktop
Before installing the driver please close/disable all background applications.
I have just tried this, and I got the exact same error message. Should I just send the card back and buy a card from NVIDIA?
Retrieving data ...