LW uses an auto backup system now just in case things like this happen. So I am not sure why, when you resumed the files they couldn't be found. It's obvious the LW download prefs have been corrupted somehow. This sometimes happens when the computer is shutdown but LW has not fully closed. LW can be very slow to close sometimes, lingering in background though not visible to the user. Control-Alt-Del to bring up window to see what programs are running before shutting down computer. Also having LW set to shut down immediately helps to reduce this from happening.

The behaviour you described sounds like how LW was unable to resume files in above scenario in versions before LW 4.12 I think it was. Since then, LW should be able to resume the files when/if this happens.

Are you sure the files are resuming at zero % or are only showing zero % after resume button is clicked. How it should work now is, you press resume from the incomplete folder in the Library window, and yes it will initially show zero % until the file actually starts downloading again, then it will show the correct previous download percentage.

So you will need to back up your resume effort with manual searches to try to find the original or other sources again to help start downloading those files again.