I periodically receive this error message (about once or twice a day) and was wondering if anyone could point light in my direction as to how to troubleshoot this error message.
%SYS-4-P2_WARN: /3 Filtering Ethernet MAC address of value zero from agent host table interface
Take a look at the release notes for CSCds69706. This message does not affect the operation of the switch in any way. This problem is fixed in 5.5(5), 6.2(1), 6.1(2).