You have to revert back to os 4.1.7 that is still available on Access webpage (and now we know why they keep that stuff still around
). This will at least get rid of the random keyboard error. Every version above that gave me trouble. So, I would rule out the loose cable or keyboard controller damage marc mentioned.
Also you will notice that playing the Indigo from the own keyboard will not give you the whole velocity range! Go figure. In addition mine had a bad key that was not responding to velocity after a couple of hits, so I returned my Indigo to the shop and kept my Virus Classic. I personally would stay away from any keyboard version of the Virus B.