If there are :things: in the dwg file thats not supported or a latest version of cad and the dwg file is holding 3d info it wont open... They must back save the DWG file for you.
If possible, have them either save to an older DWG format as Grant mentions or simply as a DXF. Failing that, they can export out as a PDF or at least print to one.
Take care, Mike
Get him to export AutoCad to PDF. That should be no problem.
Then you can easily open the PDFs in Illie.
My architect colleagues do this for me frequently.
Thanks for all of the help folks.