convert avi to dvd

[bbxrider]

i have a movie, thats 2 avi files that i want to convert to a format that i can burn to dvd-r, ntsc. i have nero 6 for burning the dvd
i thought i could use my ulead studio-8.
the wizard recognizes the avi's, at least i can play them in ulead, as i continue, i continue to creat video file, chose ntsc dvd, but get an error
'no combination of intermediate filters could be found to make connection'
so a couple of questions if possible here
1. not sure what the error means and what i need to fix it
2. for when its working, it wants to create a mpg output file, will nero recognize that as a burnable source file to burn to the cd-r file that will play on my dvd player that evidently does not play vcd's. i thought nero only recoginized iso and .vob files for burning