dimension problems

More often than not when typing a dimension such as 8 1/2" DIA. when I type the D everything freezes and I have to close DraftSight with the task manager. When I re-open the program I can only open the drawing I was working on as read only and I have to save it with a different name. My work around is to just type the numbers and then edit the line after to add the text. not good.