Is it possible to create a DVD with two formats? Like burn widescreen 24p video and a fullscreen 29.97 video on the same DVD and play either one after choosing from the MENU.
DVDA should automatically detect the correct settings of each video. Just to be sure, go to File -> Optimize DVD and check each video there. If it has the wrong settings on the right, change them. Keep in mind that if you change a setting to something that a video currently is not, DVDA will re-encode that video, which will take a long time and reduce that video's quality.