Tried that, but no luck.
Beyond this one particular case, what has me worried is this: When might it happen again? What causes it and how can it be prevented? Without knowing that, I feel like I'll have to always save multiple copies of every dvd project just in case one gets corrupted like this. It really sucks to live in fear.
Of course DVDSP sucks for a lot of reasons so maybe this will finally get me to switch to something else.
oh btw, I did find this nice little program that allowed me to at least salvage the subtitles from the corrupted project file:
http://homepage.mac.com/julifos/soft/dvdsp_subpick/index.html
Which saved me some time re-doing all those, except the timing was way off in the subtitle file, maybe because of frame rate or something.