"The Fantasticks" was a history-making musical in its modest way 26 years ago. Its small cast and modest set demands spawned thousands of productions from Albany to Addis Ababa, and the show is still playing in New York City, offering its simple wisdom and lovely tunes to a new generation.

But simplicity can be deceptive, as the production now playing at the Washington Theatre Wing in Takoma Park amply demonstrates. That uncomplicated music is actually extremely difficult, both vocally and instrumentally, and without the tonal sharpness achieved by truly skilled performers, it loses its excitement. Music director Lance Humphries, who also struggles with the piano accompaniment, has the songs plodding along, making them sound overly cautious and rather dull. Of the cast, only Melanie Metzger as the teen-age Luisa has much virtuosity as a singer; her clear and strong soprano handles the show's demands nicely.

It must be said that the show is a tiny bit dated as well. Somehow the song about a staged rape, once the grand centerpiece of the first act, falls a little flat in this age of heightened sensitivity to violent sex crimes. Other elements -- the innocent romance of the young neighbors and their disaffection and subsequent new appreciation of old values -- fare better and seem no less pertinent than they did a generation ago. The show is a little precious compared with most contemporary fare ("listen with the inside of your hand" is one typical line), but a better production could have kept the charm intact.

This version, however, is virtually soporific, with all the drive and excitement drummed out of it by plodding inadequacy.

The Fantasticks, by Tom Jones and Harvey Schmidt, directed and produced by Perry Schwartz, music direction by Lance Humphries, choreography by Karin Abromaitis, lighting by Chuck Vaughan, costumes by Ellen Mansueto. With Jeff Peters, Melanie Metzger, Keith Douglas, Jack Wilbern, Bill Seely, Doug Krentzlin, Jim Boyd, Karen Hutcheson. Harpist: Lorraine Sapp.

Final performances Friday and Sunday at the Washington Theatre Wing.