A big burst of positive energy in a medium that typically thrives on conflict, Bruce Beresford’s “Peace, Love & Misunderstanding” may not be great cinema, but its broad, crowdpleasing qualities should make it a welcome night out for femmes. With a weaker cast, this predictable feel-good item might’ve gone the Lifetime route, but there’s no denying its B.O. potential with a force-of-nature central perf by Jane Fonda, who’s graced American screens only two other times in the past 20 years. Sleeper success awaits, assuming word of mouth kicks in and the actress goes to bat in the publicity arena.

Forty-two years after Woodstock, the Flower Power movement is still blooming in upstate New York, where Fonda’s hippie-dippy Grace plays mother hen to the town’s tie-dye crowd. Though honorary matriarch of the entire town (as well as its matchmaking fertility goddess and free-loving grass dealer), Grace hasn’t spoken to her own daughter, Gotham lawyer Diane (Catherine Keener), in 20 years, and consequently has never seen her two grandkids, Zoe (it-girl Elizabeth Olsen) and Jake (“The Naked Brothers Band’s” Nat Wolff).

Diane needs a few days to collect her thoughts before signing her divorce papers, so the action trundles off to Woodstock, where the long-awaited reunion occurs less than five minutes into the pic. With an actress as gifted as Fonda, one might want the pain of that separation to register when she first sets eyes on her estranged brood. Instead, Grace tells a jokey story about a dream she had the night before. It’s a typical emotional cop-out in a script that’s intelligent, even clever at times, yet seldom perceptive.

No sooner does the family arrive in Woodstock than the film introduces locally grown, mostly recycled love interests to distract them. For vegetarian Zoe, it’s a handsome butcher named Cole (Chace Crawford). An aspiring filmmaker always seen with camcorder in hand, Jake focuses on coffee-shop sweetheart Tara (Marissa O’Donnell). As for not-yet-divorced Diane, the understandably conservative (in matters of the heart, at least) right-winger catches the eye of guitar-strumming Jude (Jeffrey Dean Morgan).

Despite all the fresh romantic possibilities in play, the most compelling moments revolve around watching Fonda have cheeky fun with her ultra-liberal persona. The cast is capable of far more than Beresford demands (Keener’s character feels especially thin), and yet the Australian helmer seems to believe the aud for such an upbeat trifle is content to settle for pretty pictures and pop songs. “Conflict isn’t interesting. It’s painful,” Zoe pouts at one point. Here, the closest thing to genuine dramatic tension is waiting for Diane to forgive Grace for not being a perfect mother. (Meanwhile, providing free pot and encouraging the teens to lose their virginity makes her pretty much the coolest grandmother ever.)

If the lesson du jour is simply “loosen up,” then the trip to Woodstock might be expected to inform Diane’s decision to separate from husband Mark (Kyle MacLachlan), but it doesn’t.

One reason “Misunderstanding” goes down so easy is that it resists any idea too complex to fit inside a fortune cookie. When a character asks Jake what his film is about, the Werner Herzog wannabe naively replies, “That’s the wrong question. What is any film really about?” From “Driving Miss Daisy” to “Mao’s Last Dancer,” Beresford has made plenty of features with a thoughtful idea at the core. This one’s content to be a group hug.