I Can't Change My Minecraft Skin On NovaSkin?

I've been trying to change my skin for along time now, by NovaSkin. I've worked hard on many skins but when ever I press "Apply", a white screen pops up and says "Not the profile page? Try to show the change skin page again.".
When ever I click it, it does nothing at all!
I really want to change my Minecraft skin~ Thanks for your help.