Yes, the DVD version is intended to be bootable. You didn't tell us enough to pin down your problem, my first impression is that it could be any of the following but it also may be something else:
  • The DVD may have been burnt at too high of a speed to boot reliably, or you may simply have a media problem (I have seen a lot of bad or marginal DVD media).

    You mention putting the DVD in the DVD drive. Is it the first optical drive on that controler and the same one that you boot the CD from? Some BIOSes seem only to boot from the first optical drive, Smart Boot Manager may help you boot from other drives.

    The DVD section of the drive may be bad or marginal (most DVD drives use a diffeerent laser for the CD and DVD section AFAIK)

It might help if you told us what does and doesn't happen when you try to boot the DVD. Does the disc even spin? Do you get the prompt screen?