It fails pretty early, in ac.scm. If I use pretty much any of the built in "languages", it breaks claiming that "interaction-environment" is unbound. This is a function that's supposed to return the present environment, used as a parameter to eval in the REPL.
If I use the R5RS language, the interaction-environment function is defined, but it doesn't help because it breaks even earlier, at (require mzscheme) in as.scm, claiming that it doesn't recognize require.
Update:
After replacing all of the interaction-environment calls with calls to current-namespace, as recommended by another commend on this forum, the first thing that failed was 'set-car!'
