Andrew, thank you. Of course it is the export function that is locked up. My apologies. I don't have GSU in front of me to look at.
Chris, Andrew is correct. You'll still have some work to do but you can certainly make a 3D drawing from a 2D import. Keep in mind that faces are frequently missing after an import from a CAD file. Adding them is as simple as tracing edges or running a Ruby script called Make Faces.
In my experience, many CAD files have problems such as lines not intersecting. In SU, an open corner means a face won't fill. If you have faces that won't fill, start looking closely at the intersections.