Well I tried all of that and work fine, but I was thinking on a way to explain this to my father and that my friend was not an easy task. Then I found this program:
Cucusoft AVI to DVD/VCD/SVCD/MPEG Converter and Cucusoft MPEG to DVD Burner
Let me tell you it took a real long time to finish but it did all i needed in a very easy way, It merged all my 3 avi files and converted to dvd mpeg format then with the Cucusoft MPEG to DVD Burner I was able to create my dvd very fast.
I got to say that it may take longer than other programs but man this is really was a really easy solution for me and this is something I can explain to my dad with no problems.
Iâ€™m not related on any way with Cucusoft, I just felt to post this here in case some has the same problem.