I've tried extracting my encrypted game, and other people have, but it always gives a fail message. This is happening on the BGM tracks, and the problem happened more than once, even after deleting the tracks that failed the first time. I swear there is nothing wrong with the tracks themselves. Why is this happening?

I'd see it as a good thing that your game can't be extracted. At least if you already have the source anyway.

The archive is probably too big (> 128 MB). Just put the BGM in a separate folder.