Try powering on the Helix while holding down footswitches 6 and 12. This puts the unit into update mode. After it powers on, open the updater. If it doesn't work the first time try it again.
You might also try a different USB port on the computer.
When I first got my LT I had some issues getting the computer to recognize it. I didn't have the same update issues you are experiencing, but I had to try 3 different computers to get it updated. After that everything worked fine with the original computer.
