Currently Being ModeratedOct 24, 2012 6:00 PM (in response to serbgirl40)
... So I'm guessing I have to change my IP address.
Not necessarily. It means your Mac has not been used on that router for so long that it assigned your Mac's IP address to another device. It will automatically issue your Mac a new one.
To change this you might want to reconfigure your router to issue DHCP leases with a longer duration. Unless this problem is nagging you constantly, just ignore it.MacBooks iMacs iPods AirPorts, OS X Mountain Lion, 27 years Apple!