UNREADABLE SCREENFONT on mac osx (10.5.8 / PPC G5)

maybe a dumbo problem.
no hints to be found in manpages or faqs.
no system messages “blender wants to use the … font” or additional fonts to be installed.

anyone who encountered this and/or could give me sth like a BLIND GUIDE through the menus to change the screenfont?

(antworten auch gern auf deutsch :wink:
thx A LOT in advance!