DSO firmware version 3.64

Following instructions at macappstore I got dfu-util installed. When I run dfu-util -a 0 -D DSO BenF APP v3.64.dfu i get:

dfu-util: Could not open file DSO for reading: No such file or directory
Karens-MacBook-Air:~ svenough$

So where do i have to put DSO BenF APP v3.64.dfu so it can find the file? Or do I have to add a patch of some sort?

Mark B Fay MMC Jr. Engineer QMED AS-E / MSC ET