I am new to MorphOS and loving it so far on Mac Mini 1.5 Ghz 512mb ram, i too cannot get youtube vids to work, i have these in my scripts folde: Facebook HTML 5 Converter, Youtube HTML 5 converter, Youtube Full screen Fix and Youtube - EZ Download, all latest from Fab's website, i can download the videos with EZ Download and that is all.
I would really like to get this working before buying the full version.