DVD Video disk has unsupported region code error

A relative of mine sent me a DVD disk but I cannot play it on my computer. I am getting an error message "This DVD-Video disk has a region code that does not match the region code set for your DVD drive. You cannot change the region code for your DVD drive."
I have a Pioneer DVD-A04S drive. I tried several DVDs of mine and it works fine. Any help will be greatly appreciated! Thank you. I am using Windows XP Home Edition with SP3.
