This is weird. In the past, when I first installed WordPress, I was able to edit my theme files via the "Presentation" in the admin panel. And just yesterday, I noticed that it no longer allows me to do so. It says, "If this file were writable.." I have already heard about the support question about changing the files to 666. But how come it happened, when I didn't even touch them in the first place? Too bad I wasn't able to check if it was really 666 before. It's 644 right now by the way.