Need some help with Nero Recode 7

Well, most of you already know that converting RM format into DVD with a WinampAVI software will give you a clear and best quality, which is know n to everybody that it is the best converter ever.

This is what I use to convert the movie of Mission Impossible into DVD Vob and other stuff. However, since WinampAVI won't allow you to burn a single thing if your file or data is over the limit restriction, which is 0.99GB is the maximum. Hence, I use Nero to recode and encode. However, Nero doesn't allow me to do that. When I clicked on add file and looked for the DVD vob converted with WinampAVI, there wasn't anything to be chosen, all I could see is blank and empty. What's the problem with it? The file size after the conversion of the movie is 2.1GB. But it seems some of the movies in RM format, after converting, which is 1.9GB, is selectable for encoding with the use of NERO, which mean that some of the file is encodable with NERO and some don't. My question is why? Do I really need to do some setting before I start the burning process?