It is hard for us to tell from long distance if your problem is in the creation of the dvd or if it is a problem with the disk and the burning process. If you are trying to make a dvd-video, it must be in a very specific format for most dvd players to recognize it and play.
First of all, what kind of video are you starting with? Is this a home movie that you have shot? Or an avi file or some other type of video that you have?
Does the dvd-r you burned play on the computer? What type of blank dvds are you using? And what speed did you burn it?
There is a free program that I recommend that works for most conversions into dvd video. It is called AVStoDVD. You can find it here: http://www.videohelp.com/tools/AVStoDVD
When you set up AVStoDVD, make certain to set the output to match the standards of your country for dvd video. The US uses NTSC standards. Most of the rest of the world uses PAL. You can change this setting in AVStoDVD by clicking on Preferences, then clicking on the Audio/Video tab.
AVStoDVD can use a free burning program called ImgBurn to do the actual burn to a disk. Or you can use your normal burning program.