Why does this part say there's a problem?

Why are the Splines not smooth, can they be?

It started as a DXF, is that the problem? I was a hell of a lotta work getting it to this point.

How do I take a DXF to Solidworks successfully?

The part is saved as a SLDPRT but uploader says it's an unsupported format.

​​​​​​​attached zip file