The last thing I wrote in my notes at the preview screening of "Uptown Girls" was "could have been worse." I guess that means some part of me was somewhat charmed by this silly, weightless yet self-serious modern fairy tale of a dead rock star's impetuously carefree daughter who must come to terms with the real world when her accountant absconds with her inheritance.

But the contrived story gets by only on the middling magnetism of its stars: Brittany Murphy as flighty, Peter-Pan-syndromed Molly Gunn and 8-year-old Dakota Fanning as Ray, an uptight little rich girl who slowly loosens up when Molly takes a job as her nanny.

As they learn neatly packaged life lessons from each other and grow into more well-round people, the laughs are often predicated on either Murphy's pratfalls (beautiful actresses playing clumsy is Hollywood's idea of making them seem "common") or the cuteness quotient of a pretty blonde child wearing Chanel, listening to Mozart, acting snooty and speaking in multi-syllabic words she can hardly wrap her mouth around.

A trio of writers and director Boaz Yakin ("Remember the Titans") attempt to bring "Uptown Girls" some gravity with plot elements involving Ray's detachment from her home-hospitalized, long-comatose father and neglectful music-label-magnate mom (Heather Locklear). "If you're mad, you don't miss people," the moppet states with a vulnerably matter-of-fact coolness in her big blue eyes. "If you stay mad, it's like you never knew them at all." But that's about the extent of the movie's depth.

The balance is characterized by its relentlessly twinkly score and breathy girlie-pop soundtrack songs about living a "charmed life" and "Crayola skies for a thousand miles, nah-nah na-na-na-nah" -- even as self-indulgent Molly faces serious ups and downs adjusting to an unprivileged life, including alienating her friends with her literal and figurative baggage after she's evicted from her cavernous Manhattan condo.

But every relationship follows a predictable, abridged arc -- be it Ray and Molly, the girl and her mother, Molly's standing up to the mother, Molly and her perfectly-coifed cardboard-cutout of a Upper West Side best friend (Marley Shelton) or Molly and the sissy-Brit toy-boy pop singer (Jesse Spencer) with whom she falls in love, but only after he tosses her aside.

Eventually coincidence and the one marketable skill Molly possesses (she creatively redesigns the singer's trademark jacket after accidentally setting it on fire) conspire to tie a neat bow on the character's growing up, while just her continuing presence seems to cure Ray of all that ails her, allowing the little girl to rediscover her childhood.

With a personality to match her bouncy hair and wispy-sundress wardrobe, Murphy brings enough blithe charisma to "Uptown Girls" to forgive some of its triteness and folly (although it's hard not to nitpick a movie with such stupid gaffes as Molly watching TV in her condo after a big deal has been made about her power being cut off). But this actress is capable of so much more than becoming another Reese Witherspoon, wasting her talents for a fat paycheck. (See "8 Mile," "Girl, Interrupted" or "Sidewalks of New York.")

Fanning ("I Am Sam," "Trapped") is very talented as well. The best scene in the movie is sold by her panicked distant recognition of "fun" as Molly spins her around her bedroom. Yet her performances are always so eerily polished and proficient that one can become distracted wondering if there's some whip-cracking nightmare of a stage mother in the wings, valuing the girl's career over her happiness.

Because of these two, "Uptown Girls" is watchable. But watchable and worth paying for are two very different things.