Unresolved Dungeon defenders help plesdr

Okay, I'm trying to mod my Dungeon Defenders save, and it opens just fine in the program, but after I change the value, the file doesn't stay modded. I'm trying to mod the mana field, and it shows that it's been changed, but when I look at it again, nothing happens.

Here's the save file:
http://rapidshare.com/files/3862686233/DunDefSave

Edit: I just tried modding it in the USB, and I got the long-winded error a couple other people posted.

Using a friend's Vista laptop, for what that's worth.