In the same way as for the SNMPv3 agent example, AgentV3, you must point the multiple agent application to the security configuration file when you instantiate the multiple agent. This is only the case for the first of the SNMP adaptor servers created by your multiple agent application. All adaptor servers created subsequently by the multiple agent are directed to their corresponding security files in the code of the multiple agent application, when that adaptor server is instantiated.
You must call the MultipleAgentV3 application inside its directory and make sure that the two security configuration files are present in the same directory.