This is a local workstation message. The router will not send such a
message out. What this message is saying is that a new device has
appeared on the network with that address but a different MAC. When the
computer comes up and cannot connect to the DHCP server to get an address,
it will randomly pick out an address and it is possible that more than one
computer will pick that address.
If you solve your DHCP problem, you will see this message go away.
Network Systems Analyst
School District of Manatee County
(941)708-8800 Ext. 1021