That is just OSX telling Mandrake to "fuck off, this is my territory".
No seriously, I don't know...maybe it is a conflict with your gfx chipset and Mandrake for PPC. Maybe your gfx card/onboard gfx chipset has some damaged ram or you may have damaged system Ram(shared wth onboard gfx chipset?).
It's hard telling. It could even just be a bad burn. Try re-burning the ISO(assuming you downloaded Mandrake).
[ August 30, 2003: Message edited by: Zombie9920 ]