Just a note, I am running windows 8.1 with an asus motherboard no serial connector. I have this unit usb to RS232/UART TTL/RS485. plugged the serial cable in one end and the usb in the other and uploaded, downloaded to the ASC1 with no errors.
I tried all my browsers. Same result.Try downloading with a different browser. A few months ago I had problems with Firefox or IE not being able to download anything successfully.
You could also try running the extractor with admin privileges. Right click run as admin. Could also try adjusting compatibility to win 7. Right click properties.