For me the problem appears while loading Widgetry-Support. I tried both under X11 and without X11.

The last line in MacOSXLookPolicy class>>initialize is the one that raises a MNU:

systemAttributes characterAttributes updatedQueryFor: Screen default defaultFontPolicy.

systemAttributes characterAttributes returns a CharacterAttributes object and it probably expected from it to return an object of class VariableCharacterAttributes, a subclass of CharacterAttributes, where updatedQueryFor: is implemented.

Bottomline: it would be really nice to have the core part separated from the GUI.

Ciao,

Ricky