LW does a rollback when you resume files ,so in theory the files should not be corrupt .
But not everyone is using LW and their client may have corrupted the file when they downloaded it , so it's a corrupted file for anyone that downloads from them .

Sadly , about 70% of the audo files you download have this problem .
The only thing you can do is open it up in an editor and try to fix the problems .

If you have audio-files wich such problems take them out of your shared folder , you don't want to share bad files do you ?
Make sure LW is not running when moving the files or you get a ugly error .