Catch error thrown if config file does not have square brackets

[chubtub]

When creating a pcrim, if the config file does not have an array as the value for File then the following error is printed to the console:
Error processing RIM command: class org.glassfish.json.JsonObjectBuilderImpl$JsonObjectImpl cannot be cast to class jakarta.json.JsonArray (org.glassfish.json.JsonObjectBuilderImpl$JsonObjectImpl and jakarta.json.JsonArray are in unnamed module of loader 'app');

This error can be reworded for clarity for the user.