Have I backed up to wrong media?

[Hotdog2]

After posting, I carried on looking thru varius threads and found my self at a compat bility table that says my settop should play all the formats.
At present I am chasing round the varius ways of writing to the discs to make them dvd-rom.
But I will take into account your dvd-r suggestion as the media certainly seems to be much cheaper.