Warning to recreation association theater groups: Do not, repeat not, attempt to put on "The West Side Waltz," no matter how appropriate its small, multi-generational cast of characters and light treatment of genteel geriatrics seem to your actors and audience, and no matter how wonderful everyone in your group thinks was Katharine Hepburn and Ernest Thompson's previous play, "On Golden Pond." If it doesn't quite go at the Kennedy Center's Opera House, with Katharine Hepburn jutting her chin inimitably, and with all the rent-controlled splendor of a West 72nd Street apartment meticulously created behind her, it's not going to go in your multi- use space. What's more, if your audience looks beyond what the playwright claims to be saying -- what each and every character is made to say over and over again -- to the actual plight of its heroine, you will send your audience home so depressed you will probably never see them again. On the surface, Thompson's play, like "On Golden Pond" (in its tart stage version rather than the softened film one) satirizes the problems of old age and celebrates a person turning feistier as age advances, rather than weakening. As the heroine moves from one cane to two, to a walker, a wheelchair and finally a sofa, alternately barking at the stupidity of others and shocking them with her calm grasp of the dirty facts of modern life, she is constantly being celebrated for displaying "gusto and style." Even the super of a decaying New York apartment house has the sole function of appearing regularly to tell the old lady how beautiful she is. All of this smacks of Gee-Grandpa-is-87- and-still-reads-the-comics-every-day. As Robert Benchley once pointed out, if he doesn't do it now, he probably never will. Besides being credited for being witty on the basis of what would be only slightly sardonic in a person of middle age, the heroine is actually forced to accommodate herself more and more to people she considers beneath her. All the other roles -- a neighbor played by Dorothy Loudon, David Margulies as the super, and Regina Baff and Ron Howard as a paid companion and her boyfriend -- are fawning morons. And the real play, whatever is said about the heroine's undaunted spirit, is that her emotional needs make her hire one fool for companionship and tolerate another for physical assistance. THE WEST SIDE WALTZ -- At the Kennedy Center Concert Hall through April 10.