The Social Security Administration each month falsely reports that nearly 1,200 living Americans have died. These clerical errors, found in a federal database ominously titled the “Death Master File,” might be darkly humorous — evoking Mark Twain’s famous quip that death reports can be greatly exaggerated — were not the consequences so severe. “It has just been one thing right after another since I found out that I was dead,” said an unsmiling Judy C. Rivers, 58, of Jasper, Ala. “Right now, I am still looking for a job. I hate to give out my Social Security number because I...