It sounds like LinuxMCE is trying to take an IP address that's already in use. Have you verified the IP addresses in your network?
Also, it seems like you aren't setting this up to be your dhcp server (only one NIC). By default LinuxMCE is going to try to bring on the DHCP server and take over your network... that would fail if miserably if 192.168.*.1 (192.168.80.1 by default) is used and half work if there is another DHCP server on the network subnet (very bad). At that point it can assign an IP address to one device that another device is already using... effectively killing your network.