help with cad closing points or lines

I have 2 slots 9/16 wide they have a slight radius,
When i put in a cam program to setit up for the cuts, and i try to have it do an inside profile, one side of the arc will show an inside path the other side will only give me an outside path.

I tried turbocad12 and autocad2009 i assume i am getting this problem from not have a closed line, i can't seem to get it to close, is there a trick i am missing, i tried close polyline but i get the same results.

Thanks gary