1099-R inherited federal pension balance

My wife inherited $91 from her late mother's Federal retirement (Office of Personnel Management) and received a 1099-R for the distribution.  During the Turbo Tax review, I keep getting an error message asking for the beginning and ending date of service for the Oregon Information Worksheet.  We have no idea when my deceased mother-in-law began or ended her service with the Federal government (Veterans Affairs).  Is there a "work-around", or should I simply leave these fields blank?