yeah, i have a couple and all of them was the same error. i switched to 5 different usb ports.
i just fixed it, i looked under device manager and saw there was 2 usb mass storage devices, i disabled one of the mass storage devices then my ds-x was detected by the program
edit
after updatin my firmware i did some of my own edits to some roms, and now blood of bahamut and kingdom hearts works on my ds fatass, but made in ore and mario luigi rpg 3 both lock up at certain parts