Mommy, I don't want to poop in the tub!

This is what Macey says to me every time I tell her it's time to take a bath. We had an incident (not me, her) a couple of weeks ago, and it has scarred her deeply. I was putting away clothes while she was playing in the tub when I heard her yell out, "MOMMY, I ALL DONE!" I went to go get her and was surprised to see her standing up, arms reaching out to me with a look of terror on her face. It wasn't until I had her wrapped up in the towel that I saw the reason for all the horror. Little poop.

So this is a conversation I have with her almost daily:

Me: Macey, you need to take a bath-y.
Macey: NO Mommy, I don't want to poop in the tub-y!
Me: You don't have to poop in the tub, Mace.
Macey: Don't havta poop in the tub?
Me: No, only if you want to.
Macey: I don't want to poop in the tub-y.

And even when I coerse her into taking a bath... I hear all sorts of random things about #2:

"Don't poop in the tub-y"
"Don't poop on the ornage (orange)"
"Don't poop on the Lucy potty"
"Don't poop on Mommy's eggs (legs)"

I could go on. This kid has some serious poop issues. She's now even scared to poop in her diaper, and will scream bloody murder when I have her sit on the potty. How can I help her overcome this fear? This is going to be zero fun for potty training, which I fully intended on starting like, last month. Randy made the suggestion that I buy the book Everyone Poops. I think I may buy it, purely for the cover picture of that poor kid who is obviously constipated.