You can use the root of any drive, it's being in the root that makes the relative paths work like they do on a CD.

Proxy and Invoke don't work on a Mac, the SmartExec script used EXEC on the PC side to launch a renamed version of proxy.exe and it used an AppleScript on the MAC side to accomplish the same thing.

Code:
function SmartExec(target)
{

   platform = $version.slice(0,3);
   
   if (platform == "WIN") 
   {
      fscommand("exec", target + ".exe");
   } 
   else 
   {
      fscommand("exec", target + "_script");
   }

}
And the AppleScript we ended up using to open his PDF files (one script for each PDF, just like proxy solution) was...

Code:
property fileName : "file.pdf"

set myPath to (path to me as string)
set AppleScript's text item delimiters to ":"
set the parentFolder to ((text items 1 thru -2 of myPath) & "") as string
set AppleScript's text item delimiters to ""
set targetFile to alias (the parentFolder & fileName)

tell application "Finder"
   open file targetFile
end tell