Suppose I ply Pat with drink and then get him to insult you. Then I am not responsible for insulting you, since I didn't insult you. But I am responsible for your getting insulted by Pat as well as for Pat's insulting you, which are harms that I imposed on you and on Pat, respectively.
On its face, the distinction is not available in the case of murder. If I ply Pat with drink and then get him to kill you, then I am responsible for killing you, since I did kill you—by plying Pat with drink and getting him to kill you. But insulting has an essential expressive role such that to get someone to insult you is not the same as to insult you.
But actually the distinction is still there in the case of killing. For there are two token acts of killing: one performed by me and one performed by Pat, with the latter being my means to the former. I am responsible for both, of course. But it is only for the first act of killing that I am responsible in a way that I can express with "I am responsible for killing you." The responsibility for the second is expressed with "I am responsible for your being killed by Pat" and "I am responsible for Pat killing you", which again indicate harms to you and Pat, respectively.
The distinction is that between action responsibility and event responsibility. I have action responsibility for getting Pat to insult or kill you. I have event responsibility for Pat insulting or killing you, and for your getting insulted or killed. I can be event responsible for any event I can intentionally cause. I can only be action responsible for actions of mine.
Now suppose that I get myself drunk in order to get myself to insult you. In that case, I am action responsible for getting myself to insult you and event responsible for your getting insulted and for my insulting you. Am I also action responsible for insulting you? I certainly did insult you. Let's fill out the cases. In my initial example, I got Pat so drunk that he intentionally but non-responsibly insulted you (perhaps Pat didn't know the effects drink has on him). In my final case, suppose that I got myself as drunk when insulting you as Pat was when he insulted you. Thus, were I not responsible for getting drunk, I would not be responsible for insulting you. But I am responsible for getting drunk. And I am clearly effect responsible for my insulting you. But am I also action responsible for insulting you?
I think not. If the answer were affirmative, then there would be an extra instance of action responsibility in the reflexive case where I get myself drunk that isn't present when I get Pat drunk. But it doesn't seem to me that there should be. Here's an intermediate case: I pay Jim to kidnap a random person and get them drunk and have them insult you. I do think an extra instance of action responsibility occurs should Jim happen to randomly kidnap me.
I think the point generalizes. When I am in the sort of state that would render you not action responsible for Aing were I to impose it on you, that token Aing is not one that I am action responsible for (though I might be action responsible for Aing still—see the murder case), even if I am responsible for being in that state. I may very well be event responsible for my Aing, of course.
But I think only incompatibilists can afford to generalize the point. For in a deterministic world, every state I'm in when acting is the sort of state that were I to impose it on you without any responsibility on your part, then you would not be action responsible for the actions the state gives rise to.
Note 1: A related distinction that I've insisted on in the past is between derivative and non-derivative responsibility. The present vocabulary is more neutral. I am inclined to think that action responsibility is always non-derivative and event responsibility is always derivative, but that is a substantive thesis, not the nature of the distinction.
Note 2: The distinction between action and event responsibility is not the Casteneda distinction between my responsibility for my Aing (i.e., my responsibility for Alexander Pruss Aing) and my responsibility for my* Aing. I can have the latter--say, when it is important to me that the insulting be done by the same person as the one getting the insulter drunk, namely me--without yet having action responsibility for Aing.