I download some 3d dwg drawings from 8020.net, but i can't open it with solidwork. i received this message

" The Solidworks DXF/DWG trasator supports DXF/DWG files of revision 12 and above. Earlier revision files may translate satisfactorily, but are not guaranteed to do so.

The drawing being imorted may be older than revision 12 and/or may contain invalid data."

Does anyone know a program that can open these files or a place to download 3030, 1530 and 1515 t-slot alum drawings.

thanks for your help.