I'm really sorry no one has responded. It's not that we don't think this issue is important, it's just that we're trying very hard to get caught up, and hadn't seen this one yet. It's true, we're running pretty far behind.
I will log this ASAP. I'm not on a PC that has our bug-tracking software right now. But, I agree with Raidergoo that, in this case, the data probably isn't recoverable.
I would always urge you, in whatever version of the game you use, to back up your files frequently. That's not to say that you should expect the game to do things like this! This is an important bug to fix. It's just safe practice, especially if, like you say, you have 300+ hours invested in it.
Will post the TT # in a bit.