A Musical Failure

So, I can't sing this song. I've been trying, very hard for several days, and it just won't happen. The tempo is too slow, or the range is too low for me or something, I just can't do it. But I really want to. I love Johnny Cash, so his is the version that I linked, but there are others. (I can't sing any of them.) This is super frustrating, because usually, I can sing whatever I want to. (Not that I'm out to win American Idol or anything like that, but typically no one runs from the room clutching their ears when I open my mouth.) *sigh* I guess it's back to musical scores and Gene Autry for me, and I guess all those awful patriotic songs, which are, for some reason, all written in the perfect key.