I take it that you do not have a copy of DataCAD? If you do, just got to File/Export. If you don't have a copy of DataCAD, then I'd be happy to convert it for you: send it to neil DOT blanchard AT verizon DOT net.
Could I ask you a huge favor? One of my projects from 1990 has come back to me as a renovation for a new owner. There's some kinda karma involved, I'm sure.
I still have the old DataCAD files, and was able to convert most of them to AutoCAD R14 DWG format.
One of them is somehow corrupt, and I can't convert it. Do you think you could convert this one to AutoCAD R14 for me? I'd be very grateful. I took the liberty of sending you the file under separate cover.