That was my initial thought as well, but I don't think so. See below. Oh also I forgot to mention that I'm launching the kix script via a shortcut as well. So the working directory is already being set via the value in the start in box in the shortcut properties. Here is the shortcut settings:

command line:
kix32.exe J:\test.kix

start in:
C:\test

And then inside the J:\test.kix:
RUN "@CURDIR\fastcall.exe"

If I do a "? @CURDIR" it does show the proper directory of C:\test. It doesn't matter what I use for the RUN line though. I can just do "fastcall.exe" or the entire path "C:\test\fastcall.exe". Either way I still get the error.