Friends with Money (15) <!-- none onestar twostar threestar fourstar fivestar -->

How do moneyed people deal with friends who suddenly don't have money and wilfully take jobs no middle-class person would touch? That is one of the more interesting questions explored in Nicole Holofcener's Friends with Money, an ensemble comedy set in Los Angeles, where money is more comfortably given to charity than lent to a friend in need.

It concentrates on the sometimes uneasy friendship between four women, uneasiness being the hallmark of Holofcener's two previous features, Walking and Talking (1996) and Lovely and Amazing (2002). The good news is that one of the quartet is played by Catherine Keener. It's quite an achievement that an actress who specialises in the traits of "problem women" - insecurity, snippiness, a thin-skinned willingness to take offence - should always manage to be so watchable. Here she plays Christine, a screenwriter who is at the crossroads with her husband David (Jason Isaacs). Her two married friends are Jane (Frances McDormand), who seems to share the burden of insecurity and snippiness, and Franny (Joan Cusack), a rich, apparently not desperate housewife.

All three are concerned about their friend Olivia (Jennifer Aniston), a woman nearing 40 but seemingly incapable of finding a decent boyfriend or pursuing a "proper" career. She has just quit her teaching job and become a cleaning woman, a move that her friends don't appreciate.She's also recovering from a recent affair with a married man, and starts dating a beefy personal trainer (Scott Caan). It's plain that the guy is a lout, but she refuses to see it. Why is she so hopeless?No telling, but it might be the reason her married friends stick close to her - their lives don't look so bad in comparison.

Holofcener's scriptwriting, sharpened by her time on Sex and the City, is often smart and funny, and she leaves room for her actors to suggest more than they're saying. As Jane, Frances McDormand plays a woman hurtling towards the menopause and mad as hell about it. "It's like we're just waiting to die," she says, turning her rage into confrontations with waiters and hissy fits in checkout queues. Her husband, played by Simon McBurney, is a more appealing character, generous-spirited and amusingly oblivious to his friends' suspicions that he's gay; the type is true to life but seldom seen in movies, which are more impatient of ambiguity.

If their marriage passes for the norm - more or less amicably muddling through - and Franny's marriage is the ideal (buttressed by wealth), then Christine's marriage to David is the nightmare, the point at which "honesty" between a couple becomes an instrument of torture. While their builders are adding a storey to their house, the foundations of their life are crumbling. When he remarks that all the junk she's eating has put weight on her behind, I heard gasps of disbelief around the room. When she replies, "Your breath smells like a dead man", you know there's no way back for these two.

Keener and Isaacs handle this antagonism plausibly, but it doesn't dispel the impression of sketchiness that haunts the film. Holofcener, a dab hand at creating tension in individual scenes, hasn't quite pulled them all together. At times, it feels light on motivation, as if we're watching highlights from a superior soap opera.

This is especially problematic in the case of Aniston, whose character has been left maddeningly opaque. We gather she's partial to dope now and then, but that would hardly explain her weird passivity and lack of drive. When the personal trainer wheedles cash from Olivia for supposedly helping with one of her cleaning jobs, she meekly complies; but when Franny ums and ahs about lending her $1,800 for a training course she flies off the handle.

Well, maybe the inconsistency is just human, and Holofcener's observation of the way money becomes a renewable source of envy, pity, worry or guilt is, for the most part, spot-on. What disappoints is how little Aniston - a gifted comedian - has done to illuminate this pivotal character. A woman who goes around department stores collecting freebie face creams can justify the habit if she lacks money; a woman who steals face cream from her clients' bathrooms is possibly in need of help. Unfortunately, the latter (and more interesting) problem is raised and then promptly ignored.

If Friends with Money feels more like a sequence of vignettes than a seamless whole, we can still admire the cleverness of the writing and the vigour of certain performances. While a full account of what middle-class Angelenos bellyache about - stolen parking spaces, waiter service, lack of ocean view - is likely to leave most people muttering, "Lend me your problems", Holofcener reveals just enough of them to keep us sympathetic. As for a friend who decides to become a cleaner, the rules are twofold: always be prepared to lend them money; never be tempted to offer them employment.