Are you using the firmware loader file? If not, download & install it as well:
Install_BC_VUP_v1.0.0.8.exe
Also, the firmware itslelf, as downloaded, is actually a "zip" file (file extension *.zip). You'll need to unzip it before loading (using the firmware loader).
That's the other common hand grenade. If you can get the browser to let the file be downloaded, it then will save it, but either changes the file extension, or adds an additional, to file extensions like *.txt, *.doc, whatever.
If it changed the file name, first change the file name back to the correct name as on Uniden's web page: BCD396T_V1_11_03.zip
Now, use PKZip, Winzip, or other software (some of it available as freeware for download) to expand the firmware file.
The resulting file should be: BCD396T_V1_11_03.scn.
That's the file that you are going to tell the firmware loader BC_VUP to load.
Others may (and probably will) disagree, but in my opinion, the process goes more smoothly if you save (or unzip) the *.scn file into the same folder that BC_VUP resides in, rather than browsing or fishing for the file location where you saved or unzipped the *.scn file.