syslog filling: address not found errors

My unix syslog is filling up with the following error:
Jan 25 13:14:37 unixserv bootpd[7224]: IP address not found: 192.168.2.197

That’s the IP address of my WinNT4.0 box.
DHCP is not running on NT, everything has been assigned static IPs. I tried setting up WINS on NT, but still the notices pile up. I noticed the sonic wall soho firewall appliance is also getting errors for the same address, Saying a UDP packet has been dropped from the NTbox address. What’s going on here?