I tested it with just the head image alone, and it still doesn't load at all. But the sprite worked for you, so it can't be the color depth or anything about the image itself.I'm not sure how to help with that issue then, if no other texture pack loads it's head sprite, then the problem is something obstructing head loading, if only your texture pack wont load, then the problem is the sprite.
Be sure to check out the properties of the image, and see if the image is not blocked.
What exactly do you mean by "blocked"? The image isn't read-only or hidden.
Edit: Upon further inspection, some of the folders are partially read-only. When I unset the folders from read-only, though, they re-set themselves. I'll have to investigate that.
Edit 2: Hang on a tick! So it turns out that the Player_0_0.png file doesn't work for female characters. That explains why it worked for you and not me, but then what head file do female characters use? They don't appear to have a different texture file.