Nil Value Error when attempting to delete a character from the Combat Tracker

[Nyiri_Hawkwing]

Trying to clear out characters that are no longer actively playing from the combat tracker and made the mistake of deleting the characters from the game first before removing them from the combat tracker. I'm now getting a 'nil value' error when I try to delete them from the combat tracker. I've tried to reload the characters, but it sees them as different from the ones that were there originally. What can I do to delete them or even to reset the combat tracker to empty so that I can add in the current active party members?