Weber's echt-Romantic opera contains some of his most innovative, subtle music. What keeps the work a rarity rather than a classic is the libretto, which is filled to bursting with spirits and serpents while lacking motivations and plausible relationships. But the conductor Leon Botstein, never one to shy from the seldom-performed, leads his American Symphony Orchestra in a soberly powerful account of the score, and the director, Kevin Newbury, takes the opera seriously, despite its problems. The cast is strong, particularly the tenor William Burden, singing with bronzed dignity.