Hi Phil,
I don't use that program either but a few things to also check:
-Make sure you're exporting 1:1 scale
-Make sure you have the drawing at 0,0 origin
I tried using Solidworks for drawing turn work but never got the dxf just right, so my cylindrical piece ended up looking like an oval piece because I didn't have the origin at 0,0.
Hope that helps-
Dave