When I save a drawing file in ProE in a DXF format and try to open the file in Auto Cad, the drawing loads fine at first, but the program will stall for around 3 seconds then present an error message INTERNAL ERROR: OCTTREE 2, and Auto Cad dies and asks me if I would like to report the error. I've read some posts about how display modes can play into the format translation (line types, hidden, wireframe...), and I've tried everything I've thought of , but to no avail. Anybody know?