I'm not sure how to do it from Windows, but modern .iso file can be written directly to dvd or usb.
Perhaps try Image Writer
as suggested here.
The utility you're using looks similar to unetbootin in that it tries to create a bootable usb flash drive from an iso file. This was needed before distibutors started shipping .img files. However, the .img files are now deprecated in favour of .iso files that can be used as .img files.
Writing the raw .iso image to a usb flash drive will turn it into a virtual optical drive that can be booted just like a live dvd.
From Linux, I use dd to achieve this.