Not sure if FileIO can write .dwg or .dxf with version 7 @dale → Yes / still No ?
you should - manually by hand - try to figure out, how to export a dwg in the command-line
you can use MacroEditor and check for commandline-Scripting in the help
start with -_export
the file extension will define the file-type.
make sure to handle spaces … something like: "_export "my file with space.dxf" "
create the command in a separate string - for more easy debugging.
string myCommand = “…”;
Rhino.RhinoApp.RunScript(myCommand, false); // see your link at the initial post.
hope this can serve as a starting-point.
all the details you will find here - just in vbScript / Rhioscript
but the concept is the same.
kind regards -tom