EDIT: Nvm used Brawlbox 0.66b and it saved fine.

Okay so I decided to try PW's Stage Expansion Hack.
I did everything right. What with the codes need to get it and everything appeared on the game, the empty stages that I can use for custom stages and what not.
Brawlbox doesn't wanna save when I try to change any of the stuff that is in the sc_selmap_en for common5.pac. I was able to save things in the sc_selcharacter.pac fine but I keep getting this error when I attempt to save any changes that were done in sc_selmap.
"The given key was not found in the dictionary."
I have no idea why its doing this. All I am doing is placing in the icons, stage preview, game of origin logo, that stuff for the stages I wanna use. But everytime I do that and try to save, that pops up and and I have no idea why it would do that. I am using SSPs made by others for the stages I am using so I don't think there should be any reason this error is popping up.
Someone, please tell me. What should I do to get Brawlbox to save? I am using the latest version and what not and I read some threads on here that people used older versions who got the same error and said it worked after that.