As I said in my first post, this only fixes the crash with the Maroon Popo costume. There's quite a few that can still crash the game, and if they've been discovered then that could explain it.
It is possible though to detect and fix all costumes that cause crashing, but it's not really doable with notepad++. I've created a version of the prop0.pak file that does fix all costumes (known and unknown), and also allows them to be seen:
All you need to do is extract this to your game's "pack" folder. This file will only work with the current TW version. I also created the file manually, and so there's a chance I messed up somewhere, or missed a costume.
EDIT: There also may be item slots other than the full body costume that can also crash, this file doesn't address those.
Works wonders thank you ! Maybe you could sticky this one link for people who don't know it's hidden here on page 5?