1 disk or 2 disk AVI, the method is the same except the joining bit.
Many of the early Pioneer DVD players have dvdr playing problems. I dont have one but a mate does.
How the dvdr is Authored, how it was burnt and speed & media used all reflect playback. All I can suggest is to start at the back and work forward, that is change your media brand (remember Princo made stuff comes under many names) and try 2x if you use 4x or 4x if using 2x. When burning with Nero, try the UDF option only and also change the UDF version from the 1.02 to the 1.5 or the 2.0), Also try the DVD-Video option. If none of these work for you, try SpruceUp, Maestro, DVDLab, IFOEdit etc to author insead of TMPGEnc DVD Author.
With these sensitive players, you have to keep trying until you find the right combination that works for you.