When you are getting this error? after setup or before the setup?

and What is the bios settings , did you disable the serail port and paralel port.

and you are using AHCI and you put your driver any port that not support compability mode such as port 5-6.

and be sure you are using working SATA cables.

and did you create 2 dvd which have two different mkext file in it.

and what is the result? can you also send the bios screens?