Well, in case a fit of curiosity about Kant strikes you, the relevant discussion is in Metaphysics of Morals (not the Groundwork) 6:390ff. Neither Hugh's interpretation nor mine is obviously correct and I think the matter is up for discussion. Hugh is right that a failure to pursue imperfect duties isn't vicious or a transgression by Kant's lights, but I think it's neverless wrong to attribute to Kant the possibility of supererogatory action. imperfect duties are flexable because they can be trumped by other dutoes, not because they can be passed over. Failure to pursue imperfect duties is still moral failure, just not a failure of the same species as moral transgression.

You should give Kant a glance though. Perhaps his work is not strictly relevant to the question of machine morality (I think he might argue against the possibility of a moral machine), but it's still very interesting stuff, even to argue against.