A 53-year-old Burlington woman pleaded not guilty today in Suffolk Superior Court to charges that she falsely claimed to have been robbed and shot at while she was driving a bus for the MBTA in 2007. Nancy Parker faces charges that include workers’ compensation fraud and filing a false report. Clerk Magistrate Gary D. Wilson released her without bail, but ordered her to return to court Feb. 28 for a pre-trial hearing. Parker allegedly concocted an elaborate story that she was robbed and a gunman fired several shots at her when she stopped to pick a young man up near Garfield Avenue and Exeter Street in Chelsea on Oct. 2, 2007.