The following information explains more about these two kinds of events.
Event ID 4302: A local sharing violation occurs when the service cannot receive an updated file because the local file is being used. This occurs on the "receive" side of the file change. The file is already replicated. However, it cannot be moved from the installing directory to the final destination.
Event ID 4304: The service cannot stage a file for replication because of a sharing violation. This occurs on the "send" side of the file change. DFSR wants to stage or copy the file for replication. However, an exclusive lock prevents this.