CD-ROM access probs.

Hi everyone. I recently downloaded the small iso of QNX6.1 from this site (the 30ish meg file) so as to have a look at QNX. Im very impressed with what Ive seen so far, but Im having probs accessing the cd-rom for some reason. Only time I can access it is when I boot with the CD in the drive, even if I boot from harddrive, which while working fine is a bit of a nusiance. Can anyone offer me any suggestions please as to what may be the problem ??
Thanks in advance

Try to boot with the alternative boot (hit ESC hit during booting, when prompt for so). This is will disable DMA.

BTW, is the CD on a slave IDE channel?