That is very extrange in Mandrake 8.0 I know that is very easy to install. During the installation, do you have booted in Graphic Mode? Or it booted in text mode? If you have booted in graphic mode, there will be the Resolution and the amount of colors, that happened to me one time when I was configuring the XFree 86.
Try to change the resolutions and the amount of colors, begging from the lowest resolution and colors, until you get that error again. If you have booted and install everything in text mode, maybe that is like SuSE that is has the CD # 1 that is the installation from Graphic mode and the CD # 2 that is for the text mode. Read your manual maybe you could find something.
I hope this will help you.