A chick flick that feels thirty years behind the times, “I Don’t Know How She Does It,” adapted from a best-seller by Allison Pearson, marvels at, or more accurately worries over, a woman’s ability to “have it all”—that is, job and family. In an age that sees more and more women executives in corporate leadership roles (not to mention politics), the movie, directly without flair by Douglas McGrath, seems a proto-feminist fable set in an age when that movement has made enormous strides, if not triumphed.

Sarah Jessica Parker does her customary cute, dithering shtick as Kate Reddy, a hard-working, bright executive at a Boston investment firm headed by Clark Cooper (Kelsey Grammar, wasted). She has a back-stabbing rival there in Chris Bunce (Seth Meyers, unfunny), but her bosses have such confidence in her that they send her out on a lot of important business trips, and that leads to her real problem—frequent absences from home. Her husband Richard (Greg Kinnear, adequate), an architect who chose to start his own firm at just the wrong time, is affectionate and supportive. But her young daughter resents her being away so much, and Kate regrets missing important moments in the life of her two-year old son—his first haircut, for example—because he’s so often in the care of a nanny.

A domestic crisis occurs when Kate gets the opportunity of a lifetime, the chance to work on a proposal for a fund aimed at retirees with New York-based legend Jack Abelhammer (Pierce Brosnan, amiable and relaxed). The task will mean even more traveling, however, and comes up just as Richard lands his first major contract. Kate’s struggle to meet both her domestic and professional responsibilities makes for the crux of the story, though there’s a subplot about how the divorced Abelhammer finds her so charming that he begins to fall for her.

Frankly, in this day and age, when so much collaboration is done on-line and firms discourage travel to save costs, Kate’s situation seems at best anomalous. So does the sexist treatment at the office, which isn’t of “Mad Men” excess but is definitely anachronistic. And, of course, the script can’t make much sense out her idea of a special investment fund for seniors, which sounds thoroughly prosaic though we’re supposed to believe it a stroke of genius.

And in any event Parker doesn’t make Kate a very interesting person. The character is filled with woe over what she sees as her maternal failings (a feeling accentuated by her insensitive mother-in-law, played by Jane Curtin), but seems unable to do anything about it but fret and go into Lucille Ball-like tizzies—at least until the end, when her big fund proposal goes big-time and given her new clout. And Parker plays her as just another variation on her “Sex & the City” template.

As for the supporting cast, Brosnan and Kinnear are both pleasant, though their joint devotion to Kate stretches credulity, given her rather irritating habits. Curtin seems an odd choice to play an old-fashioned scold, given the “liberated woman” persona she embodied on SNL years ago. (You want Dan Aykroyd to show up and say, “Jane, you ignorant slut!”) And Busy Phillips is boorish bore as the loudest of the women at the kids’ school that Kate terms the “Momsters,” stay-at-home moms who actually short-change their children while making catty remarks about wives with jobs.

But the best thing about the movie is Olivia Munn, who plays Kate’s single-mindedly ambitious secretary Momo. Her one-liners are biting—the best writing in the script—and she delivers them perfectly. A picture about Momo rather than Kate might have been much funnier and edgier.

A final observation about “I Don’t Know How She Does It” involves the decision to incorporate comments from some characters delivered directly to the camera, as though they were in some sort of documentary. The tactic is lifted from “The Office,” but it’s employed here utterly arbitrarily, a lazy and derivative script device. And it certainly doesn’t help that even though its quality has declined over the last couple of years, the sitcom is still considerably funnier than the movie.

Lighthearted social commentary is a tricky business, and “I Don’t Know How She Does It” doesn’t do it very well.