Complex Event Processing (CEP) provides a mechanism to efficiently correlate and infer conclusions about systems by means of analyzing the events they process. In areas such as the Internet of Things (IoT), Cyber Physical Systems (CPS), system monitoring or data streaming analytics, CEP is able to read events from a data stream and to generate complex events that represent situations of interest to the system owner by means of event patterns. Every time a sequence of events matches a pattern, a complex event is created and added to the data stream. The dependencies among the rules and the possibility of non-confluent behavior of CEP rulebased systems may lead to unexpected outputs when executing CEP programs. In this work, we show how to statically check and correct two particular properties of CEP systems: rule acyclicity and rule race conditions. We use Esper EPL as a CEP language, and present a tool we have developed to perform these analyses.