The American Showcase Theatre Company has been trumpeting the fact that its production of "The Fantasticks" is cast "nontraditionally," without regard to color, so the cast includes black, white and Hispanic performers. The Alexandria company's choice of colorblind casting is, in itself, laudable. But before director Jill Kamp selected the members of her multiracial troupe, she should have inquired whether they could act or sing -- the glaring lack of basic performing skills here turns the feather-light whimsy of "The Fantasticks" into a leaden ordeal.

The 1960 Tom Jones-Harvey Schmidt off-Broadway musical, a childlike variation on the Romeo and Juliet story that also playfully exposes the backstage workings of the theater, became New York's longest-running show. Its enduring charms are still occasionally apparent here, mostly in the lilting score, which includes "Try to Remember" and "They Were You." But it's a sad comment on the quality of this evening that during a love duet between the two principals, the audience's attention continually strayed to the far more engaging sounds and movements coming from the piano-harp "orchestra."

Kamp muddles the musical with heavy-handed direction that has the performers continually shouting and moving gracelessly. Even more deadly is the absence of dramatic flow -- Kamp insists on stopping the action cold before beginning another scene or a song. Opera singer Charles Williams makes a personable El Gallo, with a warm baritone and a rich speaking voice, but he is too often paired with an inferior singer, souring the effect. His daughter Lynne Williams makes a fetching Luisa, but her chirping soprano fell consistently short of the mark, and though Michael Frith invested his portrayal of Matt with lots of boyish energy, his singing was consistently uneven. As the Old Actor, Irvin Ziff struggled gamely to inject some much-needed comic relief by mugging and ad-libbing vaudevillian Yiddishisms, but even his best efforts couldn't save the show.

The Fantasticks, by Tom Jones and Harvey Schmidt. Directed by Jill Kamp; setting and lighting, David McCandlish. With John Degen, Tamora DeMar, Michael Frith, George Fulginiti-Shakar, Hugo Medrano, R. Michael O'Hanlon, Bernie Papure, Charles Williams, Keith Williams, Lynne Williams, Irvin Ziff. At American Showcase Theatre through Jan. 17.