In that case, I'd say there's an issue with the burner itself. You've clearly tried enough different brands of media -- and Taiyo-Yuden is as good as it gets, so it's almost certainly not a media issue.
I did note that there are a lot of posts r.e. media issues with the Everio Sharestation -- hopefully JVC is aware of this and will issue a firmware update.
... just for grins, have you tried using DVD+R media?