Drifter,

If you do a search for "Spurious Internal Error" you will find a few threads about it... In short - your file is lost to the world.

I have had it happen to me once or twice also. Luckily the files where quite simple, but should it ever happen to a file I use for multiple drawings... *Blind rage* would not cover it...

What's scary about this one, is that nobody knows why it happens and what you can do to prevent it (unless I missed that solution... Anyone?)

Luckily it is extremely rare... But still, getting heart palpitations when you open an important file should not be necessary. Saving often doesn't help, but saving with different file names as your progress through your drawing ensures that you can go back to an earlier version.