'ROCK' ON A ROLL

The kidvid market has sure been kind to director Don Bluth. His 1989 film, All Dogs Go to Heaven, has now sold more than 4 million copies on video ($56 million wholesale), far outstripping the movie's $25 million take at the box office. Bluth's latest feature, the animated Rock-a-Doodle, opened last April after a lengthy delay to almost uniformly poor reviews. Yet despite its meager take in theaters (about $11.6 million), Rock-a-Doodle debuts this week in the No. 2 slot on the kids' video sales chart. Elsewhere on the list, Barbie fans will be happy to see that the plastic blond has aerobicized her way back into the top 15 this week. Looking ahead, with Steven Spielberg's live-action hit Hook secure in the top position, and with FernGully...The Last Rainforest arriving in stores now, Robin Williams should be on top of the kidvid world soon. That powerful vantage point in turn bodes well for Disney's upcoming holiday blockbuster, Aladdin, which will feature Williams' voice. % LAST WEEK SALES

1 1 Hook Dustin Hoffman (Columbia, $24.95) 2 - Rock-A-Doodle Animated (HBO Video, $24.98) 3 2 The Great Mouse Detective Animated (Disney, $24.99) 4 3 Sing Along Songs: Be Our Guest (Disney, $12.99) 5 4 101 Dalmatians Animated (Disney, $24.99) 6 6 Sing Along Songs: Disneyland Fun (Disney, $12.99) 7 11 Sing Along Songs: Under The Sea (Disney, $12.99) 8 9 Alice In Wonderland Animated (Disney, $24.99) 9 10 American Tail: Fievel Goes West Animated (MCA/Universal, $24.95) 10 8 Sing Along Songs: Heigh Ho (Disney, $12.99) 11 5 The Qizard Of Oz (MGM/UA, $19.98) 12 7 Dumbo Animated (Disney, $24.99) 13 14 Tiny Toons: How I Spent My Vacation Animated (Warner, $19.98) 14 35 Dance! Workout With Barbie (Buena Vista, $19.99) 15 36 Cartoon Classics: Happy Summer Days (Disney, $12.99) For the week ending Aug. 23