How Important are Author's/Artist's comments about the Meaning of their Work?

This is a question that garnishes an astonishing amount of discussion in the circles of analytic aesthetics.  A recent article "Intention, Interpretaion, and Contemporary Visual Art" by Hans Maes (British Journal of Aesthetics 50:2 (2010) 121-138 argues that such pronouncements are defnitive.  His proof though is insufficient.  He simply observes that often when looking at contemporary art we do not understand the meaning of the work until we find out what the artist has to say about it.  An example he gives is a work by Amer Ghada called 2002.  I am nervous about putting an image of Amer's on my blog, but here's a  link.  Just looking at the work itself (considering for example only the most abstract image in the link) does not allow one to know that the abstract images are derived from pictures found in pornographic magazines.  Arthur Danto observed this in a review of Amer's paintings for The Nation.  Now I do agree that this sort of thing is common and that we often today accept what the painter says about her work, and see the work in terms of that afterwards.  But does this really prove that we should always do so?  It seems that this is just typical of certain kinds of avant-garde work in our century:  the work is not just what you see but also what is said by the artist about it.  But this does not mean that what the artist says about a piece determines what it means in a definitive or absolute sense.  It is still the case that the artist can say misleading things about the meaning of the work.  Of course the real position at issue here is whether the meaning of the work is determined by the artist's intention at time of completion of the work.  This position is called Actual Intentionalism.  However the position simply assumes that there is something in the artists mind, something like a sentence, which is the artist's intention.  The idea is that we find out the artist's intention if we find out the sentence or sentences that accurately describe that state of mind.  Yet is there such a thing?  Aren't intentions simply constructions, often constructions after the event?  Aren't artist's comments about the meaning of their work such constructions?  If I say something to you and you ask me what I meant, am I looking into the past and finding the actual intention I had when saying it, or am I constructing something that will work for the occasion?  Isn't it myth to think there really is a thing that corresponds to what we call the actual intention?  In short the kinds of cases Maes discusses do not speak strongly in favor of Actual Intentionalism, as he argues, but simply speak in favor of using that theory when looking at works of this sort.  By the way, if you are already familiar with Amer's work and have seen examples that are less abstract, it is fairly obvious that these lines are derived from pornographic images, so the claim that you need to rely on her words to understand the work is a bit disigenuous. What is in the mind at the time of creation of the piece?  Are unconscious phenomena allowed? If so, could the artist be channeling the spirit of the age unbeknownst to her/him? If so, what does this do to the claim that the meaning of the work is what the author/artist intended it to mean?