Regardless of the environment the error or problem occurred in, always attempt to reproduce the behavior in Studio. If the error occurred while you were building and testing rules in Corticon Studio, then you're already in the right place. If the error occurred while the rules were running on a test or production deployment environment, then obtain a copy of the Ruleflow (.erf file) and open it, its constituent Rulesheets (.ers files), and its Vocabulary (.ecore file) in Studio.