If Only the Pants Fit Right The 1975 Canadian movie "Lies My Father Told Me" was a charmer. A coming-of-age story by Ted Allan, about his early-20th-century poverty-saturated Jewish childhood in Montreal, the film was an Oscar nominee even. And now it's a musical. The National Yiddish Theater - Folksbiene production, which opened Thursday in the Baruch Performing Arts Center's cozy basement theater, remains charming. But with a couple of exceptions, Elan Kunin's music, lyrics and orchestrations detract from the experience rather than enhance it. There are plenty of good things to be said about this production. Chuck Karel, as the boy's grandfather Zaida, has a rich, comforting, toasty-warm stage presence. Jonathan Raviv is thoroughly believable as Harry, the father of the title; his latest get-rich scheme involves permanent-press trousers, which would be perfect except for their weirdly baggy knees. Russell Arden Koplin is lovely as Annie, the mother, who spends Act I gracefully pregnant. Alex Dreier, who plays young David, does an impressive job with a truly challenging role for an actor of any age. "What's With the Knees," the song with the silliest title, is the show's darkest and best, sung by an angry, put-upon Harry. "Bankrupt," the number with the most depressing title, is the silliest, as David belts the word joyously to the neighbors. His father's bad business judgment means they will not be moving out of their beloved neighborhood. But most of Mr. Kunin's melodies sound like tunes you have heard a thousand times before, and his lyrics often seem more concerned with rhyming than saying anything. At least twice, the words "beyond compare" were tacked on at the ends of lines for no other discernible reason. But when the orchestra falls silent, Bryna Wasserman's adaptation and direction shine. Several supporting characters - the constant complainer Mrs. Tanner (Renée Bang Allen), the Marxist tailor (Gordon Stanley) and the neighborhood prostitute (Leisa Mather) - seem well worth knowing. And it's nice of them invite the hooker to the bris.