To prove my point, here is a random sample from Harry Potter and the Chamber of Secrets (pg. 187-188):
Harry ducked swiftly behind his cauldron, pulled one of Fred's Filibuster fireworks out of his pocket, and gave it a quick prod with his wand. The firework began to fizz and sputter. Knowing he had only seconds, Harry straightened up, took aim, and lobbed it into the air; it landed right on target in Goyle's cauldron.So, in a page and a half we have five adverbs, two of which are the super-evil speech attribution adverbs, and three of which are within one line of each other.
Goyle's potion exploded, showering the whole class. People shrieked as splashes of Swelling Solution hit them. Malfoy got a faceful and his nose began to swell like a balloon; Goyle blundered around, his hands over his eyes, which had expanded to the size of a dinner plate -- Snape was trying to restore calm and find out what had happened. Through the confusion, Harry saw Hermione slip quietly into Snape's office.
"Silence! SILENCE!" Snape roared. "Anyone who has been splashed, come here for a Deflating Draft -- when I find out who did this --"
Harry tried not to laugh as he watched Malfoy hurry forward, his head drooping with the weight of a nose like a small melon. As half the class lumbered up to Snape's desk, some weighted down with arms like clubs, others unable to talk through gigantic puffed-up lips, Harry saw Hermione slide back into the dungeon, the front of her robes bulging.
When everyone had taken a swig of antidote and the various swellings had subsided, Snape swept over to Goyle's cauldron and scooped out the twisted black remains of the firework. There was a sudden hush.
"If I ever find out who threw this," Snape whispered, "I shall make sure that person is expelled."
Harry arranged his face into what he hoped was a puzzled expression. Snape was looking right at him, and the bell that rang ten minutes later could not have been more welcome.
"He knew it was me," Harry told Ron and Hermione as they hurried back to Moaning Myrtle's bathroom. "I could tell."
Hermione threw the new ingredients into the cauldron and began to stir feverishly.
"It'll be ready in two weeks," she said happily.
"Snape can't prove it was you," said Ron reassuringly to Harry. "What can he do?"
"Knowing Snape, something foul," said Harry as the potion frothed and bubbled.
BUT...does anyone really care about this? Because let's look at something else this scene gives us...some damn fine description, and some bits that even make me laugh out loud. It also gives great characterization for Snape - the hush when he finds the firework (although maybe it shouldn't have been "sudden," which I've heard is on a lot of agent/edior hit lists), and the fact that he can whisper a threat and it is even more menacing than if he had shouted it. SPOILER ALERT AHEAD FOR BOOK FIVE. DON'T READ THE REST OF THIS PARAGRAPH IF YOU HAVEN'T READ THROUGH ORDER OF THE PHOENIX (although if you haven't read them by now, that's really not my fault) Something else that this scene gives us is an incling that Snape can read Harry's mind, which of course we find out later is something he's quite skilled at. And all in this little scene in potions class.
So even though this writing sample does show some signs of weak writing (and even though JKR put an adverb in the title, the TITLE, of her seventh Harry Potter book, Harry Potter and the Deathly Hallows), how many people really care? Her skill as a world-builder, storyteller, foreshadower and ability to keep us involved allows us to forgive her love of adverbs. Would her writing possibly be better if she took the adverbs out? Maybe. But then these books would be so great that no one else would ever want to read anything, ever, and the rest of us would all be out of dreams/jobs.
Proof that, once again, if you're a good enough writer, you can break any rule you damn well please.