Hi tripjacks and welcome,
This sounds like a verification error with VSO, Fab's default burn engine.
First off, are you able to play the disc in your burner?...in your standalone player?
The verification process in VSO is worse than a bad joke...totally worthless.
Go into Common Settings and untick this feature.
If you're interested in verification...use Img. It works and is reliable.
It's also possible that the disc didn't finalize (close session) properly.
Here's a method to force Finalization if this is the issue.
DVDFab Finalize a disc
Right click on the Fab Icon >
Left click Properties >
Left click Find Target >
Left click PcSetup.exe >
Left click on the + in front of Patin-Couffin driver >
Now left click once to select your burner >
Right click on the selected burner >
Navigate to the bottom of the dropdown to Finalize the media