Imagine being invited to dinner and being served stale and bitter leftovers. That describes Neil Simon's 31st play, "The Dinner Party," despite a stylish presentation by Potomac Theatre Company. Regardless of some fine individual performances and the professional-level production, the troupe is unable to make palatable the muddled menu Simon has cooked up for it.

The much-married playwright seems to have used this 1999 play primarily to express a malevolent cynicism about love and marriage. "The Dinner Party" starts out nicely enough as an unusual farce but then veers into introspective, frequently sour melodrama. This play seems destined to be a confusing effort for actors and audience alike, making it an odd choice to produce. But then one reads director Patricia Woolsey "is working towards her registration as a drama therapist," and the selection of Simon's exercise in personal psychodrama is understandable. But this play doesn't need a therapist; it needs Doc Simon to perform major surgery.

First, he might separate the two disparate halves of this play, performed without intermission over 1 hour 45 minutes. Then he can write two plays, a comedy and a melodrama. This one begins with an intriguing set of possibilities in the elegant private dining room of a Parisian restaurant. Five people, three men and two women, have been enigmatically invited to a dinner party. The men, all strangers, arrive first. Then two women appear, and the mystery deepens because they are two of the fellows' ex-wives.

So far it's appealing, an amalgam of an Agatha Christie-ish mystery and Simon's trademark clever New York neuroticism, although uselessly transplanted to Paris. Some of his old wit shows as the couples trade zingers, such as when Mariette (Jo Klein-Duke) complains to Claude (Jeff Westlake), her ex, who is railing about the costs of their divorce settlement. "You were never this materialistic when we were married," she chides. "Of course not," he shoots back. "I had all my material."

But by the time their mysterious host shows up, the play has lost much of its humor, settling into a somber, bizarre autopsy of failed marriages, particularly one emotionally unhealthy and rather sordid (for a comedy) union.

The cast is faced with negotiating awkward scenes, with the audience expecting punch lines but getting such gloomy observations as, "In marriage, people are always cruel to each other," and, "I used your body as an outlet for all my repressed anger."

Woolsey tries to solve the problem by having one of the couples wildly overact. Perky Erika Claire flits about rather than moves, waving her arms like a windmill, making her Yvonne hyper rather than mousy, as written, while Stuart Fischer, as her twice-divorced husband Albert, unsuccessfully plays the nebbishy character as a male ingenue.

The show almost seems salvageable whenever Westlake's Claude is talking. Almost all of the laughs are generated by Westlake, with expertly timed slow burns and his manner of biting off words exquisitely adding comic punctuation. Klein-Duke is a good match for him as the earthy Mariette. Tom Howard projects self-assured certainty as tough, abusive businessman Andre, while Michelle Trout, as his ex, Gabrielle, displays quiet elegance heroically struggling with a character who is simply not believable as written.

Designer Jared Davis has created a realistic deluxe restaurant setting, colorfully detailed and perfect down to the murals on the walls. Performing in the large, well-appointed Blair Family Center for the Arts at the Bullis School, Potomac Theatre Company puts on a production at a first-rate level. Simon's play, however, is cut-rate pathology.

"The Dinner Party," performed by Potomac Theatre Company, concludes this weekend at the Blair Family Center for the Arts on the campus of the Bullis School, 10601 Falls Rd., Potomac. Showtime is 8 p.m. Friday and Saturday and 3 p.m. Sunday. For tickets, call 301-299-8571. For information, visit www.potomactheatreco.org.

Erika Claire of Gaithersburg plays Yvonne Fouchet, and Stuart Fischer of Bethesda is Albert Donay.