Poorly formatted file when exported as DXF ?

[Bald Eagle]

I'm doing some work that requires generation of files in DXF format, and the LaserCAD program from LightObject
( http://www.lightobject.com/AWC608-Commercial-DSP-CO2-Laser-Engraving-Cutter-Controller-P321.aspx )
doesn't seem to like what VISIO spits out.
I'll get simple boxes or bounding boxes for what I drew, but a lot or all of the drawing details seem to be lost.

I've taken to exporting in SVG, then opening that in Inkscape, and then exporting to DXF from there, but there seems to be some issues with the SVG format, and I wind up losing the proper scaling.

Is there something I can do to troubleshoot why the DXF file doesn't seem to work?
Options or features or defaults that need to be tweaked?