I tried opening your DXF in another program and the lines are like the way you described. That means Aspire converted your original line to more CAD friendly vectors/sketch.
Also since we now know DXF from Aspire is not what you anticipated try PDF export and import it to Inkscape. With PDF Aspire should not separate vectors into multiple segments. You can use Inkscape to convert it to DXF, I have found it maintains your vectors correctly, but I recommend exporting DXF and image file to overlay on top to confirm successful conversation. I found sometimes DXF deviates from the original vectors, posted a comment on that subject here.