Bootcamp Error - "Software Update"

I'm receiving the error "Can't install the software because it is not currently available from the Software Update server." when I reach the end of Step 2 in this process (selecting the Windows ISO and installing). I believe I have the right 64-bit Windows 10 ISO and my Mac is up to date. I am not sure what Software Update the error is referring to. I have enough space but can not move past this error, even after deleting the ISO and re-downloading.