Use nero vision.
Select make a DVD video, then on content screen select Add Video Files.
Select the files in the folder, I think selecting all of them nero will automatically combine the files into a single movie. Get past the menu and preview screens, then I believe on the burn settings screen nero will say something like “This video contains more pal than NTSC content. Would you like to convert to pal?” Select no, then make sure in the video settings it’s set to NTSC. I’ve been working on a guide just for this situation of using Vision. Look for my post coming up about creating a DVD using vision.