Hey Sylonkiller, thanks for the report! Just wanted to check, do you have the Card Game Combat plugin above the Deck Editor plugin in the Plugin Manager? If you hit F8 to open the console while running the project, you should see a message that says "Please make sure IsiahCGCCardTypes is placed underneath IsiahCardGameCombat".
We believe that might be the cause of this error. Let us know if you continue having an issue after rearranging the plugins.