TmpgEnc Plus 2.5 amp; VobSub broken dvd, machines, function, recently

andy

Hi.  I'm a bit baffled and I hope someone can help.  I have
2 XP machines both have TmpgEnc Plus and VobSub 2.23

I recently tried to convert a Divx6 .avi to dvd using TmpgEnc and it didn't pick up and embed the subtitles.  Now that function is broken no matter what input video I use.  I have tried removing ffdshow, removing and reinstalling VobSub and
played with the priorities in TmpgEnc.  Nothing fixes it.  Looking at the setup on the machine that's still working doesn't provide a clue.  So I'm guessing that some utility or
codec pack I installed messed things up.  Has anyone run into
this?  Usually when this breaks reinstalling VobSub fixes it right up.