Okay I reinstalled gambit v4.2.3 with latest patches and I reinstalled the latest snow and ...
jeremie$ snowman *** WARNING -- Variable "_" used in module "extio.o2" is undefined *** WARNING -- Variable "define*" used in module "extio.o2" is undefined *** WARNING -- Variable "extio/v1.0.3" used in module "extio.o2" is undefined *** WARNING -- Variable "i/o" used in module "extio.o2" is undefined *** WARNING -- Variable "lgpl/v2.1" used in module "extio.o2" is undefined *** WARNING -- Variable "obj" used in module "extio.o2" is undefined *** WARNING -- Variable "package*" used in module "extio.o2" is undefined *** WARNING -- Variable "port" used in module "extio.o2" is undefined *** WARNING -- Variable "snow" used in module "extio.o2" is undefined *** WARNING -- Variable "snow-force-output" used in module "extio.o2" is undefined *** WARNING -- Variable "snow-pretty-print" used in module "extio.o2" is undefined *** ERROR IN | extio.o2| -- Operator is not a PROCEDURE (#!unbound #!unbound)