[Willie Green]

The usage is correct. The pronoun reference is to a continuing subject in the essay and is not a reference to Toni Morrison's . On top of that, Toni Morrison's is not an adjective, it is a noun in the possessive case.

I agree. The word "her" is merely an objective case pronoun used as the direct object of the verb "enables". As a direct object, there is no requirment that it refer back to the subject of the sentence or its modifiers. In fact, if not taken in context of information not contained in the sentence, the word "her" could easily refer to a person other than Toni Morrison. Perhaps Toni Morrison's genius is enabling some other female to create novels, similar to a ghost-writer.

[RightWhale]

Yes, that would be the best interpretation assuming the sentence was written by someone with a practical knowledge of grammar.

[John Valentine]

Your point is on the money, but I fear it would be lost on Mr. Kevin Keegan and other weak minded.

The part of this story that amazes (and scares) me is how easily this nitwit was able to sway the ETS over to his point of view.

[supercat]

I agree. The word "her" is merely an objective case pronoun used as the direct object of the verb "enables". As a direct object, there is no requirment that it refer back to the subject of the sentence or its modifiers. In fact, if not taken in context of information not contained in the sentence, the word "her" could easily refer to a person other than Toni Morrison.

Good point. Not sure such a construct would make sense with that particular sentence, but similar structures certainly work:

Bob sometimes gets stressed. Chopin's music helps him relax.

Without the first sentence, the pronoun in the second would clearly refer to Chopin. With the first sentence, though, it clearly refers to Bob.

[Sir Gawain]

In fact, if not taken in context of information not contained in the sentence, the word "her" could easily refer to a person other than Toni Morrison.

You could come to that conclusion even with the context clues, which is exactly why the sentence is incorrect.