open-output-file: cannot open output file: "C:/tmp/shashd39M2tCqX6"
It looks like the official arc2 distribution is being used here, which isn't smart about pathnames, so something in arc.arc, ac.scm, or something like that is just blindly using /s. If the Anarki is being used, then this bug should have been fixed. But as I said, I have a Mac, so I'm really just guessing here.