I have several spilt backups that don't play on one player I have but play fine on another. I suspect it being player compatability. Is there a way to redo the DVDs to make them playable?
It's probably the media you're using.
You should check to see why this has happened so it doesn't happen again,..these custom splits where they done on +R type discs ? and if so did you set booktype to DVD-Rom ?
And at what speed did you burn them? Do any of your backups on the same media play on the problem standalone?