NEW YORK — Susan Bernardo trusted her stockbroker. She wound up losing a fortune. Her broker, David Harris, advised her to sell $400,000 worth of relatively safe municipal bonds, she says, and sink the proceeds into real estate and energy partnerships in hopes of earning more income. She had received the money from a settlement after her husband died in an accident and needed it to raise her small son. More than six years later, those investments are in trouble. The stream of interest payments she used for …