I hate to suggest spending money when I’m not 100% sure it will help, but this is something to try (and only $80, so it’s not gonna break the bank).
Try buying Roxio Toast. Instead of burning from DVD Studio Pro, just burn a disk image to the hard drive. You’ll get the video_TS and audio_TS folders on your computer. Use Toast to burn those to the DVD.
Here’s what I DO know. When I used to use Finder to burn DVDs ages ago I would sometimes get discs that worked in other players and sometimes not. Toast has an option to set where you specifically tell it you’re burning a DVD…not just a data disc. That fixed the problem for me.
Now, I would ASSUME that DVD Studio Pro would know what it’s doing and this shouldn’t be an issue…but I kind of feel like it would be worth your money to give it a shot. But like I said, I’m not really sure. Don’t buy this unless you’re feelilng a little adventurous.
And I second the suggestion for Verbatim discs.