Thought I'd try to offer another option.
It is simple to use, but Nero isn't the best to encode from avi to DVD. It's far better to use a proper encoder for the process (TMPGEnc, CCE, QuEnc [latter = free]). There are tonnes of good guides you can find to use program(s) that will produce much better results than nero.
http://www.doom9.org/conversionguides.htm
http://www.afterdawn.com/guides/
Those are two good starting points. In the past I have used either DVD2SVCD or The FilmMachine programs for the process, but both require the use of an external encoder.
Good luck