"Sins of Silence," 8 to 10 p.m. Tuesday, Channel 2. Lindsay Wagner's CBS movie, originally scheduled for Dec. 5, finally premieres in the last week of the winter ratings sweeps. Wagner tries to look plain as Molly McKinley, a former nun who runs a rape-crisis center. In a milder version of Jodie Foster's "The Accused," a defense lawyer tries to put the victim on trial after a teen presses charges against an arrogant young man from a rich and powerful family. As Sophie DiMatteo, a girl with a bad reputation, Holly Marie Combs from "Picket Fences" carries more than her share of the film's dramatic load.