I was trying to offset a line by 1/2 the distance of 3.150. I selected offset and entered 3.15/2 as the distance. DraftSight ignored this and said I needed to enter a valid dimension. This is very similar to this problem https://swym.3ds.com/#community:70/iquestions:20990 in that both values involve 315.  

This was not a problem with earlier versions.