Desperate need of help! Corrupt file

Just an FYI for anybody that comes on this thread. 

In the computer world, they say there are two kinds of people: those who make regular backups, and those who haven’t lost data - YET. Your computer WILL bargle your stuff. If you use SL, at least once an hour, you need to ask yourself the Question. “If my computer or SL wrecks my project right now, will I be upset?” That’s the answer to “Should I make a backup right now?” 

You don’t want your solution to lost or bargled data to be, “Rebuild the course from the beginning.”  You want, “Go back through your backups until you find one that isn’t corrupted.”