Sometimes when someone else burns a CD (or DVD in this case), it writes it in a format that not every DVD player can read. I have had this happen to me many times, where only the DVD drive that burnt the DVD could read its contents. But, before we jump to this conclusion, there are a few things you can do.
The first step would be to go to your friend, pop in that burnt DVD, run Nero's CD/DVD speed utility, and perform a Disk Quality check. This should give you an idea if the disk was burnt properly or poorly, and it would also give you enough information to determine/find out if the media itself is of good or poor quality. If it is of poor quality, then I would suggest that your friend update the firmware of his DVD burner (from the manufacture's site) and either purchase better quality DVD media to burn to, or attempt to burn the DVD again (as with the newer firmware, disk writing could be improved).
I would also update the firmware on your DVD drive, as there is the possibility that it might be able to read that DVD after it has been updated.
Other possibilities include your DVD drive not being able to read either + or - DVD disks, so if you feel adventurous, you could try to burn it to a disk of the other type of format.
Raven