Well Lenn, I am no expert on this but I have messed with similar issues before, so here is my best guess so be kind if I am wrong.
I am not sure of the appraoch you used but I suspect the problem might be with the format it is in.
You might just need to reformat the digital file with a video converter or equivlent there of and than reburn it.
Different DVD's can play different formats, some play all.
HEre is a list of the "Top 10 Free Video Rippers, Encoders, and Converters". Maybe Rich or someone has more insight?
Here one approach to turning a you tube video to a disc, is this similar or different? http://www.ehow.com/how_5096015_burn-dvd-youtube.html