OK - got it working. If you are having trouble with pipe read issues try this sequence.
close all windows for Hakchi2.
Unplug NES mini from PC USB port (but keep cable in back of NES mini)
Start Hackchi2
click upload games
wait for message entitled something like "waiting..." which outlines a few steps to take and has an "install" link at the bottom.
[MAKE SURE NES POWER IS OFF]
NOW - plug cable into PC USB port
press and hold reset on NES
press power on NES
release power button
release reset button
you should hear the windows "new device" chime. If not, it hasn't worked.
If you do hear the chime, message should disappear and it's all gravy from that point on.