All I can say is all the equipment I have, from the first USB-1 cable I purchased with Scan Control for my Uniden 780s, 296s and 796s, the USB-1 supplied when I purchased my BCD 396T and all the other cables I have gotten with the original 246, BCD396T and the newest 396XT and 996XT all work just fine with FreeScan at 115200 bps on my Windows XP laptop. There were no problems whatsoever installing any of it.
The cable is your problem and is easily resolved.
If you look at the USB-1 cable, you'll see a cylindrical object. Inside that cylinder is a component called a chipset which converts the USB port on your computer into a serial port.
The original USB-1 cable, which you have, had what was called an "HXA" chipset. Windows 8.x doesn't "like" that older HXA chipset. Thus as you have seen, the computer and scanner won't talk with each other.
What is needed is a cable having a newer chipset (which is the "HXD" chipset).
The newest versions (manufactured in the past year or so) of the USB-1 cable have that HXD chipset.
So I'm sure if you get a new USB-1 cable from Uniden, your problem willl be resolved. Just be sure you download and install the driver (as noted on the cable when you get it) before connecting the new cable.
(I had the same problem and got a USB to Serial adapter with the HXD chipset and was able to program my scanners with Windows 8.x. That was before Uniden came up with the revised cable.)