Running into problems as well. I, in theory, installed the drivers, but the install apparently failed.
Here's what I get from the DOS window when I try to flash a cart:
C:\NESmaker\NESmaker_4_1_0\Flasher\INL-retro-progdump_map30\host>inlretro.exe -s
scripts\inlretro.lua
Matching PID/VID found and opened, but unable to communicate to device, verify d
rivers installed!!!
[ERROR] (source/usb_operations.c:159: errno: None) Could not find INL retro-prog
USB device
open_usb_device went to error
freeing device list
deinitializing libusb
[ERROR] (source/inlprog.c:320: errno: Bad file descriptor) Unable to open INL re
tro-prog usb device handle.
Fatal error encountered, exiting.
C:\NESmaker\NESmaker_4_1_0\Flasher\INL-retro-progdump_map30\host>pause
Press any key to continue . . .