I think you can get walk.lisp to work in this lisp by making this change: 176c176 < #+(or openmcl (and :Coral :mcl)) --- > #+(and :Coral :mcl) I don't have a PPC machine to try openmcl on, and in the x86-64 linux case it has some problem finding the foreign functions; if you do try it again, please let me know what happens.