What are you trying to play this video on? If you want to watch on a stand alone dvd player, check to see if that player can handle xvid or divx avi files without conversion. Those types of players usually have a little divx logo on the front of the player.
If it can, then you normally just have to burn the file as data onto a dvd. There are several free burning programs that can do this. I suggest either ImgBurn or CDBurnerXP.
If the player cannot use divx or xvid avi files, then you have to convert to dvd-video. I suggest DVDFlick for this process. Make sure that the dvd the program produces is correct for your area (PAL for most of the world, NTSC for the US). Look in the settings for this. You can also set it to burn automatically once the conversion is finished if you wish. DVDFlick is free to download and use.
Now, if nothing will burn on your dvd burner, that is a different type of problem. Tell us the make and model burner that you have, the operating system you are using, and the burning program that you have now. Posting a log file from the failed burn would help also.