The problems encountered in this thread show why MIT Scheme will only be used for academic toy programs. Better to use GNU Guile for practical tasks. Advantages of GNU Guile over MIT Scheme:
* Reported problems will be fixed
* Code base is covered by more unit tests
* Up to date and comprehensive documentation
* Large and active community (non-deserted mailing list and IRC channel with 100+ users)
* Relied on by practical programs such as GnuCash, Guix, LilyPond, GNU Artanis, etc.