@echo off
set arc_dir=C:\Program Files\ARCF
mzscheme -mf "%arc_dir%\as.scm"
This one worked for me. I'm not sure if removing the [][]'s from the file and making it windows line breaks mattered, but at least I had to move some ""'s around to get it to work.
Now just trying to get the launch-an-arc-script script working (from outside the repl). The script that is elsewhere on the website works on linux, but not windows ;). Damn pipes.