DXF is not ideal for RF/microwave layout, because there is no clear definition of a filled area. From my experience, ADS does quite a good job in reading DXF, but it really depends what DXF shapes you have used. Closed POLYLINE with zero width for the boundary has become an inofficial standard for filles polygons in PCB systems when exporting to DXF, and that works fine in ADS.
If your DXF layout comes from HFSS, the problem might be in the DXF file already. Have you checked the file with a DXF viewer? If you want to upload the DXF file, I can have a closer look.
"Port setup needed to be corrected." does not sound like a DXF related problem.