Dman, export your AutoCAD files as 3ds. Make sure you have facet and view resolutions set fairly high if you're exporting cylindrical or curved surfaces. Import 3ds object into LW modeler by choosing "Import Object", choose "all files", 3ds object will show up. I'd recommend reducing polygons in object once it's in LW Modeler, then make sure 1) geometry is all there and 2) polygon surface normals are pointing in the right direction. HTH
To all of you, thank you for all your help. I lurk here on occasion and find this forum to be extremely valuable because of the experienced and knowledgeable artists who generously give their time to assist in LW problem-solving.