I am having this EXACT same problem. DVD with subtitles. I demuxed from oringial DVD using StreamClip software. Everything checks clear in Encore until I write it. It writes subtitles and then I get them error message. No idea what to do.
FYI, I’m trying to write to a double-layer DVD. Would that have anything to do with it?
Did you get your problem resolved? If so, pleast let me know what you did. I have to have this to client tomorrow, if possible.