I downloaded grc-0.65 (stable) and grc-0.69 (stable). The former
(using Run.py) brings up a window and looks to be working; there are
no "bus error"s. The latter (using Editor.py, and after removing the
"gtk" check) works as well. Both of these were tested using the
exact same Python install. Thus the bug seems to be in GRC itself,
not in my MacPorts install. - MLD