Well first off I would suggest a visit to this site. Pay particular attention to the installatin notes. It may or may not help. Your specific error does not appear, so it may be a hardware incompatabilty. Would need more on the specs to analyse that. Check your hardware at Mandrake and see what they say.
Mandrake 8.1 errataNext I would say, did you buy copies or is it a download, if it is a download you may have corrupted data on the CDs.
Thirdly I would suggest that if you can you should head for a later version of the software, 8.2 is very stable, and 9.0 is the latest (and therby having the best hardware support).