The only way to fix the .customchar is to replace it with a working one. But never forget to keep the configuration and the character settings in harmony!
And always keep a backup of a customchar, with characters equipped with the most original stuff.
This was an educational project.
Transformers: Fall of Cybertron mod. A character setting (.customchar).
This setting includes characters which are set with the very basic, original elements, so it is compatible with the original configuration and other mods if and only if the mod is extended and doesn't miss elements that the original configuration does.