I think everyone is offering solid advice.
Personally, I would try signals' suggestion first as it is the simplest method and may work.
As cholla said, the settop recorders do not record in a format that is truly compliant with DVD-ROM structure. It is DVD-VR and contains the folders as described by cholla, ie., VIDEO_RM & VIDEO_TS folders and not VIDEO_TS and AUDIO_TS folders.
In my own experience, Fab is able to handle this format only intermittently...probably more often successful than not, but I really haven't done many.
With any of the Fab failures, I have run the files through Img build mode and then successfully burned to a disc with Img.
If I can anticipate the next question...I don't have a clue as to why Fab can handle some recordings and not others.
If I fracture a leg and become incredibly bored at some future date, maybe I'll try to figure it out...