Do you have any friends or relatives with new or newish dvd players. Try your disks out on theirs. It may be your particular player either isn't overkeen on the brand of media or isn't so keen on dvd-r/rw media or doesn't like the way your softw is burning/formatting it.

Yes all these things can play a part. Some players are touchy. Before I bought my player I tested a no. of my disks (different brands & dvd-/+/r/rw) out on them using 3 different dvd formatting & burner apps. I wanted to be sure I could get a player that could take what was thrown at it. In fact I took my original one back b/c I found it couldn't play ones burnt with a particular softw (so I obviously didn't test it out initially enough.) I do a lot of business with them plus I hold a trade card so I get things at trade price. I was a touch lucky I guess.

Try a different brand of media. What model of player do you have? What brand of media are you using?

Have you considered posting on either the http://www.videohelp.com/ forum or the http://forum.dvd-guides.com/ forum. No doubt there's also probably a forum for Sonic Now...

I use a mac & I don't know about the windows versions of dvd authoring & editing apps. So to try to work out your problem is a little difficult. I can only make comparisons to the types of issues you may come across.