This routine works with Acad14, Acad2k, but I did not include the doslib arx modules for those platforms. Get them from www.mcneel.com
Xref overlays are not added with the "Add resolved xrefs" button, only attached xrefs. If anyone needs this option, let me know and I may add it.
The path to the .zip file must not contain spaces (the paths to the included files can)