This is particularly a problem when running mongod as a windows service since the message is lost.
When starting with just --logpath but on the shell the warning is sent to the current shell as opposed to the log path.
.\mongod.exe --snmp-master --logpath C:\data\mongod.log
2013-09-26T17:04:03.891-0700 log file "C:\data\mongod.log" exists; moved to "C:\data\mongod.log.2013-09-27T00-04-03".
Warning: no access control information configured.
(Config search path: c:/Utils/snmp/etc/snmp;c:/Utils/snmp/share/snmp;c:/Utils/snmp/lib;c:\Users\Sridhar/.snmp)
It's unlikely this agent can serve any useful purpose in this state.
Run "snmpconf -g basic_setup" to help you configure the mongod.conf file for this agent.