I think the term "creative" has been muddied here.

There is no doubt an artificial intelligence could "create" something. Some picture, some series of musical notes, ect. That would be no greater challenge for it than forming a sentence. It need simply boil the language of the medium down to zeros and ones, analyze what has had appeal and what has not, add in some "golden ratio" of whatever the medium in question is. But that in and of itself is not "creative" as most people view it.

Creative, in the arts for example, is something more profound. Something that produces emotion, produces a visceral reaction.
In order to be able to do that, on purpose, the A.I. would need to be capable of having a visceral reaction, feel an emotion. Comedy is a good example to use...the A.I. would have to find something the it finds funny in order to truly understand, beyond the simple timing and structure of a joke, how to produce a genuine laugh in others.

I won't call this impossible, I will merely say "I'll believe it when I see it."