I think it's a port used by DHCP server which issues you the IP address.
I would think you should allow Kerio to listen to it and acknowledge, but an expert needs to confirm.
Are you having internet problems?
This description of various windows ports does NOT include ME, so I don't know if it may have changedhttp://support.microsoft.com/kb/832017
Normally port 67 and 68 go together.