A document expert retained by CBS News for the disputed "60 Minutes" story on President Bush's National Guard record said yesterday that she had warned the program that the memos involved "had problems" and that she had questioned "whether they were produced on a computer." Asked whether CBS had taken her concerns seriously, Linda James, a forensic document examiner in Texas, told The Washington Post: "Evidently not." Tuesday's Question: Confirmation hearings get underway today for Rep. Porter J. Goss (R-Fla.), a former CIA