The odds that you get them back at the point where you have lost them (most likely due to a system crash or by shutting down the computer while LW was still active in the processes, which possibly caused the bak file to become corrupted) are not great.
You can go to LW> Library>Incomplete and highlight the files and click resume. In the worst case they will resume at 0%.
Sorry pal, no better news for that......
