For error on wyrmkin.. well.. not sure about your progress or where you are in making it, but I am kinda suspecting that you don’t have all the matching files yet.
When you make a new class, you need all the files in there to work (heroes, raid, upgrades, localization, effect (if any)), and all renamed to match. One small break could break all.
Instead, would suggest this. Usually first I just mod one of the classes’s .info and effect and art asset (while keep it the same name), till I am happy, before I copy it out and make a new class out of it.
...............................................
Class Mods
NEW: COURTESAN | UPDATED: Assassin | Pit Fighter | Surgeon Mesmer | Trap Maker ( Still need work: Shield Miaden )